Skip to main content

Risk factors for postoperative pneumonia in patients undergoing hip fracture surgery: a systematic review and meta-analysis

Abstract

Background

Postoperative pneumonia (POP) is a devastating complication that can frequently occur after hip fracture surgery. This study aimed to quantitatively and comprehensively summarize the risk factors for POP following hip fracture surgery.

Methods

PubMed, Embase, and Cochrane Library were systematically searched for studies assessing risk factors for POP following hip fracture surgery. The pooled odds ratio (OR) and standardized mean difference (SMD) between patients with and without POP were calculated. Evidence was assessed using the Newcastle–Ottawa scale.

Results

Ten studies including 37,130 patients with hip fractures were selected. POP occurred in 1768 cases with an accumulated incidence of 7.8% (95% confidence interval [CI]: 0.061–0.094). Advanced age (SMD: 0.50, 95% CI: 0.10–0.90), male sex (OR: 1.50, 95% CI: 1.12–2.01), American Society of Anesthesiologists physical status scale ≥3 (OR: 3.17, 95% CI: 1.25–8.05), chronic obstructive pulmonary disease (OR: 2.05, 95% CI: 1.43–2.94), coronary heart disease (OR: 1.82, 95% CI: 1.27–2.60), arrhythmia (OR: 1.49, 95% CI: 1.04–2.15), congestive heart failure (OR: 1.41, 95% CI: 1.14–1.75), chronic kidney disease (OR: 2.09, 95% CI: 1.28–3.41), and cerebrovascular accident (OR: 2.14, 95% CI: 1.60–2.85) were risk factors for POP. Hemoglobin (SMD: -0.14, 95% CI: − 0.25 to − 0.03), albumin (SMD: -0.97, 95% CI: − 1.54–-0.41), blood urea nitrogen (SMD: 0.20, 95% CI: 0.03–0.37), alanine aminotransferase (SMD: 0.27, 95% CI: 0.10–0.44), arterial oxygen pressure (SMD: -0.49, 95% CI: − 0.71–-0.27), time from injury to surgery (SMD: 0.13, 95% CI: 0.08–0.17), and surgery within 48 h (OR: 3.74, 95% CI: 2.40–5.85) were associated with the development of POP.

Conclusion

Patients with the aforementioned risk factors should be identified preoperatively, and related prophylaxis strategies should be implemented to prevent POP following hip fracture surgery.

Peer Review reports

Background

Hip fractures are a major health problem and the number of hip fractures is expected to increase by approximately 2% annually over the next 30 years [1]. Hip fractures are associated with increased risk of morbidity and mortality [1,2,3]. Furthermore, the coronavirus disease pandemic, has forced an unprecedented period of challenge for the management of patients with hip fractures [4].

Postoperative pneumonia (POP) is a devastating complication that can occur after hip fracture surgery [5, 6]. However, few studies have been performed to elucidate this complication and investigate patients with hip fracture and POP. The incidence of hip fracture-related pneumonia has been reported to range from 4 to 15% [7,8,9]. Evidence has shown that POP is associated with various predisposing factors, including older age, male sex, multiple medical comorbidities, and hypoalbuminemia [7,8,9,10,11,12,13,14].

With the progress in medical technologies and aftercare of patients, clinicians are increasingly focusing on the prevention and treatment of POP. To medically optimize patients and provide better perioperative care, identifying various potential risk factors is important for POP. To the best of our knowledge, no formal systematic review and meta-analysis has investigated and summarized the risk factors for POP following hip fracture surgery. Therefore, this meta-analysis aimed to summarize the risk factors for the development of POP in patients undergoing hip fracture surgery. The results of this study are potentially beneficial for clinicians to identify high-risk patients and help prevent postoperative POP following hip fracture surgery.

Methods

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [15]. Patient consent and ethical approval were not required because this study was a meta-analysis of published studies. Two authors (KHS and SBH) independently searched and reviewed the literature, assessed the quality, and extracted data. Disagreements were resolved through discussions or negotiations with a third independent author (SBK). Inter-reviewer reliability was assessed by study screening and selection, quality assessment, data extraction, and result pooling using the kappa statistic (κ). The κ value for the data extraction ranged from 0.88 to 1.00.

Search strategy

MEDLINE/PubMed, Cochrane Central Register of Controlled Trials, and EMBASE were exhaustively searched to identify original studies that included patients with hip fracture with POP published before January 4, 2022. The search terms, Medical Subject Headings terms, and their combinations searched in the title/abstract field of the search engines were as follows: “hip,” “fracture,” “hip fractures,” “pneumonia,” “lower respiratory tract infection,” “pulmonary infection,” “factor,” “risk,” and “predictor.” No other restrictions, including language, were applied. The references of the selected articles were also reviewed to identify relevant articles.

Eligibility criteria and study selection

Two independent authors (KHS and SBH) screened all the titles and abstracts. Initially selected articles were further reviewed for inclusion according to the following inclusion criteria: (1) Cohort and case-control studies if they reported analyses of the predictors of POP in patients undergoing hip fracture surgery. (2) POP occurred after hip fracture surgery and recurited patients without pneumonia at baseline, (3) comparison between patients with POP as the case group and patients without POP as the control group; (4) accessible full-text articles; and (5) studies reporting sufficient information to extract and calculate relevant standardized mean difference (SMD) or odds ratio (OR) with 95% confidence interval (CI). The specific reasons for the excluded articles are shown in Fig. 1.

Fig. 1
figure 1

PRISMA flow diagram. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses

Data extraction

Two independent authors extracted data from the eligible studies (KHS and SBH). Disagreements were resolved through discussion and consensus with the third author (SBK). Data were extracted according to the following descriptive information: (1) study characteristics, including the name of the first author, year of publication, study country, and study design; (2) patient demographics, such as the number of patients with or without POP, age, sex, and the incidence of POP; (3) significant risk factors for POP; and (4) number of citations for each potential risk factor for POP after hip fracture surgery.

Quality assessment

The methodological quality of each included study was evaluated using the Newcastle–Ottawa scale (NOS) [16]. The scale includes selection, comparability, and outcome domains. The selection domain has four categories; comparability domain, two categories; and outcome domain, three categories. A study was awarded a maximum of one star for each category in the selection and outcome domains. A maximum of two stars was assigned to the comparability domain.

Statistical analyses

ORs or SMDs with corresponding 95% CIs were estimated and pooled across studies to assess the association between POP and various potential risk factors. A meta-analysis was performed for each factor (n ≥ 2), which was presented as an effect size of the 95% CI. The adjusted data were used maximally when available. The inconsistency index (I2) was determined, and a χ2-based test of homogeneity was performed. If I2 was < 50%, the fixed-effects model (Mantel–Haenszel method) was used due to low heterogeneity. I2 ≥ 50% was considered a significant heterogeneity. The random-effects model (DerSimonian–Laird method) was used, and a “leave-one-out” sensitivity analysis was performed by sequentially deleting one study to determine the source of heterogeneity [17]. After excluding each study, an analysis was performed to determine the existence of heterogeneity. When 10 or more studies were included, a small study publication bias was assessed using funnel plot analysis. The significance level was set at p <  0.05. All statistical analyses were performed using RStudio v.1.0.143 (RStudio Inc., Boston, MA, USA).

Results

Search results

Figure 1 shows a detailed summary of the study’s identification and selection process. A total of 1305 articles were identified after the initial search. After eliminating 286 duplicates and 918 ineligible articles based on titles and abstracts, the full text of 101 articles were reviewed. After excluding 91 articles without information of inclusion criteria, 10 articles [7,8,9,10,11,12,13,14, 18, 19] were finally selected for the meta-analysis.

Study characteristics

The characteristics of the included studies of POP are shown in Table 1. All studies were published in English and from 2016 onwards. All the included studies were retrospective cohort studies. A total of 1768 patients with hip fracture had POP and 35,362 patients without POP. The risk factors of POP reported in individual studies are summarized in Table 1.

Table 1 Characteristics of the included studies

Risk of bias analysis

The risk of bias assessment of the included studies is summarized in Table 2. The NOS scores of the selected studies ranged from 8 to 9. Methods of the cohort selection and outcome assessment were clearly stated in all studies. Most studies excluded persons with pneumonia preoperatively. Most studies accounted for confounding factors using standard statistical regression techniques.

Table 2 Quality assessment of included studies

Meta-analysis results

Crude accumulated incidence of POP was 4.8% (1768/35,362) with an accumulated incidence of 7.8%. (95% CI: 0.061–0.094; I2 = 94%). Heterogeneity could not be resolved using sensitivity analyses. Potential risk factors were classified into four categories: basic demographic predictors, medical comorbidity predictors, surgical characteristic predictors, and baseline laboratory predictors. Detailed results for each factor are presented in Tables 3 and 4.

Table 3 Pooled risk of demographic characteristics and comorbidities for postoperative pneumonia following hip fracture surgery
Table 4 Pooled risk of baseline laboratory data and surgical characteristics of pneumonia following hip fracture surgery

Basic demographic predictors

Advanced age (SMD: 0.50; 95% CI: 0.108–0.90; p = 0.01; I2 = 90%), male sex (OR: 1.50; 95% CI: 1.12–2.01; p <  0.01; I2 = 72%), and the American Society of Anesthesiologists physical status (ASA) scale ≥3 (OR: 3.17; 95% CI: 1.25–8.05; p = 0.02; I2 = 90%) were significantly associated with a high risk of POP (Table 3). Significant heterogeneity was found for the pooled results of advanced age, male sex, body mass index, and ASA scale. After sensitivity analyses, heterogeneity was resolved, and the significance did not change (Additional file 1). A funnel plot of sex was symmetrical and suggested a low risk of publication bias (Fig. 2).

Fig. 2
figure 2

Funnel plot of sex (male) between postoperative pneumonia and no postoperative pneumonia groups

Medical comorbidity predictors

Patients with anemia (OR: 1.55; 95% CI: 1.16–2.08; p <  0.01; I2 = 85%), chronic obstructive pulmonary disease (COPD) (OR: 2.05; 95% CI: 1.43–2.94; p <  0.01; I2 = 52%), coronary heart disease (OR: 1.82; 95% CI: 1.27–2.60; p < 0.01; I2 = 56%), arrhythmia (OR: 1.49; 95% CI: 1.04–2.15; p = 0.03; I2 = 0%), congestive heart failure (OR: 1.41; 95% CI: 1.14–1.75; p < 0.01, I2 = 5%), chronic kidney disease (OR: 2.09; 95% CI: 1.28–3.41; p < 0.01; I2 = 0%), and cerebrovascular accident (OR: 2.14; 95% CI: 1.60–2.85; p < 0.01; I2 = 22%) were more likely to develop POP after hip fracture surgery (Table 3). Significant heterogeneity was found for anemia, COPD, coronary heart disease, and dementia. After sensitivity analyses, heterogeneity was resolved, and the significance did not change (Additional file 1).

Baseline laboratory predictors

Lower preoperative hemoglobin (SMD: -0.14; 95% CI: − 0.25 to − 0.03; p = 0.01; I2 = 46%), lower preoperative serum albumin (ALB) (SMD: -0.97; 95% CI: − 1.54 to − 0.41; p < 0.01; I2 = 95%), higher preoperative blood urea nitrogen (BUN) (SMD: 0.20; 95% CI: 0.03–0.37; p = 0.02; I2 = 35%), higher preoperative alanine aminotransferase (SMD: 0.27; 95% CI: 0.10–0.44; p < 0.01; I2 = 0%), and lower partial pressure of oxygen in arterial blood (SMD: -0.49; 95% CI: − 0.71–-0.27; p < 0.01; I2 = 0%) indicated an increased risk of POP (Table 4). Significant heterogeneity was observed in the meta-analysis of ALB and creatinine levels. After sensitivity analyses, heterogeneity was resolved for the results of serum creatinine levels without changing the significance (Additional file 1). However, sensitivity analyses could not determine an influential study with high heterogeneity in the ALB level.

Surgical characteristic predictors

Patients who underwent hip fracture surgery that was delayed for > 48 h from admission or injury had a significantly higher risk of developing POP (OR: 3.74; 95% CI: 2.40–5.85; p < 0.01; I2 = 0%) (Table 4). Significant heterogeneity was found for surgery type (arthroplasty vs. osteosynthesis) and the time from injury to surgery. After sensitivity analyses, the heterogeneity was resolved, and the intergroup difference in time from injury to surgery was significant (SMD: 0.13; 95% CI: 0.08–0.17; p < 0.01; I2 = 0%) (Additional file 1).

Discussion

The present study extensively reviewed and summarized the predictors of POP in patients undergoing hip fracture surgery. A total of 34 predictors were available for meta-analysis, of which 15 predictors, namely, male sex, advanced age, ASA scale ≥3, anemia, COPD, coronary heart disease, arrhythmia, congestive heart failure, chronic kidney disease, cerebrovascular accident, time from injury to surgery, delayed surgery > 48 h after admission or injury, lower preoperative hemoglobin and ALB levels, lower partial pressure of oxygen in arterial blood, and higher BUN and alanine aminotransferase levels, were statistically significant.

POP occurs frequently in patients undergoing hip fracture surgery, particularly in older patients. Results of this meta-analysis revealed that the overall prevalence of POP was 4.8%, which was comparable to the previously reported range of 4.1–15.3% in patients with hip fracture [7,8,9, 11]. POP is closely associated with prolonged hospital stay and significantly increased mortality [5,6,7,8]. It is directly associated with patient prognosis. Therefore, identification and medical optimization of high-risk patients associated with these risk factors are increasingly important.

Advanced age and male sex have long been associated with adverse postoperative morbidities, including POP, in non-cardiac and orthopedic surgeries [20,21,22,23]. Airway inflammation and pneumonia increase with age because of swallowing and immune dysfunctions [24,25,26]. In addition, impaired spirometric lung age, which is correlated with advanced chronological age, is a well-known risk factor for POP [27]. Furthermore, male patients might have more extensive smoking histories, which can modify lung cell biology and impair mucociliary clearance by the increased number of abnormal cilia. In the same context as impaired lung function, the present study found that patients with lower partial pressure of oxygen in arterial blood were more susceptible to POP development.

In terms of basic demographic data predictors, this meta-analysis also found that ASA scale ≥3 was a significant risk factor for POP following hip fracture surgery, consistent with results of previous studies [28, 29]. Therefore, it is needed to give more attention to monitor elderly male patients, particularly those with current status of smoking, dependent functional status, and higher ASA scale, so that early detection could be achieved and prevention strategies could be implemented to reduce POP incidence.

The presence of medical comorbidities has a significant impact in the development of POP after hip fracture surgery. The present study found that anemia, COPD, coronary heart disease, arrhythmia, congestive heart failure, chronic kidney disease, and cerebrovascular accidents were significant risk factors for POP. In particular, comorbid COPD dramatically increases the risk of POP development in patients undergoing hip fracture surgery. COPD is a common condition in elderly patients with hip fractures, and is associated with increased risk of death and postoperative complications [30, 31]. Patients with COPD are in a state of chronic systemic/vascular inflammation and immune system derangements with upregulated C-reactive protein and increased production of inflammatory cytokines and tissue factors [32,33,34]. Additionally, limited gas exchange and impaired mucociliary clearance of pathogens can predispose patients with COPD to postoperative pulmonary complications [35, 36]. Targeted interventions to reduce the risk of pneumonia are essential in patients with COPD. Potential interventions for COPD include the use of incentive spirometry, elevation of the head of the bed, early ambulation with pain control, and institution of oral hygiene with chlorhexidine [37].

Previous evidence has suggested that anemia is a significant risk factor for postoperative complications, including POP and increased mortality [38, 39]. Consistent with previous studies, the present study showed that patients with comorbid anemia had an increased risk of POP. In the same context, the pooled results showed an increased risk of POP in patients with lower baseline hemoglobin levels. Thus, medical care in the perioperative period, including patient blood management, should be optimized in patients with comorbid anemia to decrease complications, including POP following hip fracture surgery [40].

Evidence suggests that pneumonia is associated with various medical comorbidities, including coronary heart disease, arrhythmia, congestive heart failure, and chronic kidney disease [41,42,43,44,45,46]. Cerebrovascular accidents are well-known risk factors for dysphagia and pneumonia [8, 47, 48]. Consistent with previous evidence, the pooled results of the present study showed that coronary heart disease, arrhythmia, congestive heart failure, chronic kidney disease, and cerebrovascular accident were significant risk factors for POP following hip fracture surgery. Generally, co-existing medical morbidities are unmodifiable. However, clinicians should have detailed information on coexisting diseases to assess the risk of POP and identify high-risk patients to apply preventive strategies.

Measurement of ALB level can provide an index of severity of protein-energy malnutrition in patients with hip fractures [49]. Preoperative hypoalbuminemia is a well-described risk factor for perioperative morbidity and mortality in patients undergoing orthopedic surgery [50]. In addition, BUN level is frequently elevated in patients with pneumonia because of hydration and increased reabsorption of urea by the kidneys [51, 52]. An elevated BUN/ALB level has also been reported as an independent predictor of mortality and pneumonia severity [51, 53]. Abnormal liver function test results are common in patients with pneumonia. Patients with low ALB or elevated alanine aminotransferase levels show increased mortality and length of stay [54]. Several lines of evidence suggest that the lung liver axis is characterized by a shared and prominent feature of pneumonia with a hepatic acute-phase response [55, 56]. In the same context, the present study found that lower ALB, higher BUN, and higher alanine aminotransferase levels as baseline laboratory predictors were associated with POP development.

Importantly, the present study also found that the time from injury to surgery and delayed surgery for over 48 h after admission or injury were significantly associated with the development of POP. The impact of delays in hip fracture surgery on postoperative complications and mortality has been the object of scientific discussion. Most studies have shown that delays in surgery can lead to worse outcomes, such as mortality, pain, complications, and length of stay [57,58,59,60,61,62]. Therefore, the international clinical practice guidelines recommend early hip surgery within 48 h of admission, if possible [63].

This study has several strengths. This systematic review and meta-analysis is the first to investigate risk factors for POP in patients undergoing hip fracture surgery. In addition, this meta-analysis was based on the most recent studies published within the last 5 years. Nevertheless, this study has several limitations. First, only retrospective studies with low levels of evidence were included. A general limitation of meta-analyses of observational studies is that the result may be a precise, but biased estimate due to inherent biases and confounding in the original studies. We assessed carefully the quality of the component studies and performed sensitivity analyses excluding studies with a high risk of bias. Second, some of our findings showed a significant heterogeneity and require careful interpretation. However, after sensitivity analyses, the heterogeneity was resolved (I2 < 50%) for most results, except for some variables, such as alcohol consumption, ALB level, and the time from injury to surgery. Third, the small sample size might limit the generalizability of the results. Well-designed studies with a large sample and high quality are required in the future.

Conclusions

This study summarizes numerous predictors of POP in patients undergoing hip fracture surgery. The results can be used to predict the risk of POP development after hip fracture surgery and also provide foundation for future studies. Advanced age, male sex, anemia, diabetes, COPD, coronary heart disease, arrhythmia, congestive heart failure, chronic kidney disease, cerebrovascular accident, surgery over 48 h after injury or admission, lower preoperative serum hemoglobin or ALB levels, lower partial pressure of oxygen in arterial blood, and higher BUN or alanine aminotransferase levels might contribute to the development of POP after hip fracture surgery.

Availability of data and materials

All data generated or analyzed during this study are included in this published article and its additional information files.

Abbreviations

POP:

Postoperative pneumonia

PRISMA:

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

SMD:

Standardized mean difference

OR:

Odds ratio

CI:

Confidence interval

NOS:

Newcastle–Ottawa assessment scale

ASA:

American Society of Anesthesiologists physical status

COPD:

Chronic obstructive pulmonary disease

References

  1. Brauer CA, Coca-Perraillon M, Cutler DM, Rosen AB. Incidence and mortality of hip fractures in the United States. JAMA. 2009;302:1573–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Lunde A, Tell GS, Pedersen AB, Scheike TH, Apalset EM, Ehrenstein V, et al. The role of comorbidity in mortality after hip fracture: a nationwide Norwegian study of 38,126 women with hip fracture matched to a general-population comparison cohort. Am J Epidemiol. 2019;188:398–407.

    Article  PubMed  Google Scholar 

  3. Stewart NA, Chantrey J, Blankley SJ, Boulton C, Moran CG. Predictors of 5 year survival following hip fracture. Injury. 2011;42:1253–6.

    Article  PubMed  Google Scholar 

  4. Ciatti C, Maniscalco P, Quattrini F, Gattoni S, Magro A, Capelli P, et al. The epidemiology of proximal femur fractures during COVID-19 emergency in Italy: a multicentric study. Acta Biomed. 2021;92:e2021398.

    CAS  PubMed  PubMed Central  Google Scholar 

  5. Lo IL, Siu CW, Tse HF, Lau TW, Leung F, Wong M. Pre-operative pulmonary assessment for patients with hip fracture. Osteoporos Int. 2010;21:S579–86.

    Article  PubMed  Google Scholar 

  6. Vestergaard P, Rejnmark L, Mosekilde L. Increased mortality in patients with a hip fracture-effect of pre-morbid conditions and post-fracture complications. Osteoporos Int. 2007;18:1583–93.

    Article  CAS  PubMed  Google Scholar 

  7. Bohl DD, Sershon RA, Saltzman BM, Darrith B, Della Valle CJ. Incidence, risk factors, and clinical implications of pneumonia after surgery for geriatric hip fracture. J Arthroplast. 2018;33:1552–6.

    Article  Google Scholar 

  8. Lv H, Yin P, Long A, Gao Y, Zhao Z, Li J, et al. Clinical characteristics and risk factors of postoperative pneumonia after hip fracture surgery: a prospective cohort study. Osteoporos Int. 2016;27:3001–9.

    Article  CAS  PubMed  Google Scholar 

  9. Salarbaks AM, Lindeboom R, Nijmeijer W. Pneumonia in hospitalized elderly hip fracture patients: the effects on length of hospital-stay, in-hospital and thirty-day mortality and a search for potential predictors. Injury. 2020;51:1846–50.

    Article  CAS  PubMed  Google Scholar 

  10. Chang SC, Lai JI, Lu MC, Lin KH, Wang WS, Lo SS, et al. Reduction in the incidence of pneumonia in elderly patients after hip fracture surgery: an inpatient pulmonary rehabilitation program. Medicine (Baltimore). 2018;97:e11845.

    Article  Google Scholar 

  11. Shin KH, Kim JJ, Son SW, Hwang KS, Han SB. Early postoperative hypoalbuminaemia as a risk factor for postoperative pneumonia following hip fracture surgery. Clin Interv Aging. 2020;15:1907–15.

    Article  PubMed  PubMed Central  Google Scholar 

  12. Wang Y, Li X, Ji Y, Tian H, Liang X, Li N, et al. Preoperative serum albumin level as a predictor of postoperative pneumonia after femoral neck fracture surgery in a geriatric population. Clin Interv Aging. 2019;14:2007–16.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Xiang G, Dong X, Xu T, Feng Y, He Z, Ke C, et al. A nomogram for prediction of postoperative pneumonia risk in elderly hip fracture patients. Risk Manag Healthc Policy. 2020;13:1603–11.

    Article  PubMed  PubMed Central  Google Scholar 

  14. Zhao K, Zhang J, Li J, Guo J, Meng H, Zhu Y, et al. In-hospital postoperative pneumonia following geriatric intertrochanteric fracture surgery: incidence and risk factors. Clin Interv Aging. 2020;15:1599–609.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535.

    Article  PubMed  PubMed Central  Google Scholar 

  16. Stang A. Critical evaluation of the Newcastle-Ottawa scale for the assessment of the quality of nonrandomized studies in meta-analyses. Eur J Epidemiol. 2010;25:603–5.

    Article  PubMed  Google Scholar 

  17. Cumpston M, Li T, Page MJ, Chandler J, Welch VA, Higgins JP, et al. Updated guidance for trusted systematic reviews: a new edition of the Cochrane handbook for systematic reviews of interventions. Cochrane Database Syst Rev. 2019;10:ED000142.

    PubMed  Google Scholar 

  18. Ji Y, Li X, Wang Y, Cheng L, Tian H, Li N, et al. Partial pressure of oxygen level at admission as a predictor of postoperative pneumonia after hip fracture surgery in a geriatric population: a retrospective cohort study. BMJ Open. 2021;11:e048272.

    Article  PubMed  PubMed Central  Google Scholar 

  19. Wang X, Dai L, Zhang Y, Lv Y. Gender and low albumin and oxygen levels are risk factors for perioperative pneumonia in geriatric hip fracture patients. Clin Interv Aging. 2020;15:419–24.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Gupta H, Gupta PK, Schuller D, Fang X, Miller WJ, Modrykamien A, et al. Development and validation of a risk calculator for predicting postoperative pneumonia. Mayo Clin Proc. 2013;88:1241–9.

    Article  PubMed  Google Scholar 

  21. Bohl DD, Ahn J, Rossi VJ, Tabaraee E, Grauer JN, Singh K. Incidence and risk factors for pneumonia following anterior cervical decompression and fusion procedures: an ACS-NSQIP study. Spine J. 2016;16:335–42.

    Article  PubMed  Google Scholar 

  22. Nagle RT, Leiby BE, Lavu H, Rosato EL, Yeo CJ, Winter JM. Pneumonia is associated with a high risk of mortality after pancreaticoduodenectomy. Surgery. 2017;161:959–67.

    Article  PubMed  Google Scholar 

  23. Ally SA, Foy M, Sood A, Gonzalez M. Preoperative risk factors for postoperative pneumonia following primary total hip and knee arthroplasty. J Orthop. 2021;27:17–22.

    Article  PubMed  Google Scholar 

  24. Carpagnano GE, Turchiarelli V, Spanevello A, Palladino GP, Barbaro MP. Aging and airway inflammation. Aging Clin Exp Res. 2013;25:239–45.

    Article  PubMed  Google Scholar 

  25. Ebihara S, Ebihara T, Kohzuki M. Effect of aging on cough and swallowing reflexes: implications for preventing aspiration pneumonia. Lung. 2012;190:29–33.

    Article  PubMed  Google Scholar 

  26. Janssens JP, Krause KH. Pneumonia in the very old. Lancet Infect Dis. 2004;4:112–24.

    Article  PubMed  Google Scholar 

  27. Okamura A, Watanabe M, Mine S, Nishida K, Kurogochi T, Imamura Y. Spirometric lung age predicts postoperative pneumonia after esophagectomy. World J Surg. 2016;40:2412–8.

    Article  PubMed  Google Scholar 

  28. Hackett NJ, De Oliveira GS, Jain UK, Kim JY. ASA class is a reliable independent predictor of medical complications and mortality following surgery. Int J Surg. 2015;18:184–90.

    Article  PubMed  Google Scholar 

  29. Yang CK, Teng A, Lee DY, Rose K. Pulmonary complications after major abdominal surgery: National Surgical Quality Improvement Program analysis. J Surg Res. 2015;198:441–9.

    Article  PubMed  Google Scholar 

  30. de Luise C, Brimacombe M, Pedersen L, Sorensen HT. Chronic obstructive pulmonary disease and mortality following hip fracture: a population-based cohort study. Eur J Epidemiol. 2008;23:115–22.

    Article  PubMed  Google Scholar 

  31. Regan EA, Radcliff TA, Henderson WG, Cowper Ripley DC, Maciejewski ML, Vogel WB, et al. Improving hip fractures outcomes for COPD patients. COPD. 2013;10:11–9.

    Article  PubMed  Google Scholar 

  32. Bhat TA, Panzica L, Kalathil SG, Thanavala Y. Immune dysfunction in patients with chronic obstructive pulmonary disease. Ann Am Thorac Soc. 2015;12(Suppl 2):S169–75.

    PubMed  PubMed Central  Google Scholar 

  33. Gan WQ, Man SF, Senthilselvan A, Sin DD. Association between chronic obstructive pulmonary disease and systemic inflammation: a systematic review and a meta-analysis. Thorax. 2004;59:574–80.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Thomsen M, Dahl M, Lange P, Vestbo J, Nordestgaard BG. Inflammatory biomarkers and comorbidities in chronic obstructive pulmonary disease. Am J Respir Crit Care Med. 2012;186:982–8.

    Article  CAS  PubMed  Google Scholar 

  35. Smetana GW, Lawrence VA, Cornell JE. American College of Physicians. Preoperative pulmonary risk stratification for noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med. 2006;144:581–95.

    Article  PubMed  Google Scholar 

  36. Vogelmeier CF, Criner GJ, Martinez FJ, Anzueto A, Barnes PJ, Bourbeau J, et al. Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease 2017 report: GOLD executive summary. Respirology. 2017;22:575–601.

    Article  PubMed  Google Scholar 

  37. Kazaure HS, Martin M, Yoon JK, Wren SM. Long-term results of a postoperative pneumonia prevention program for the inpatient surgical ward. JAMA Surg. 2014;149:914–8.

    Article  PubMed  Google Scholar 

  38. Foss NB, Kristensen MT, Kehlet H. Anaemia impedes functional mobility after hip fracture surgery. Age Ageing. 2008;37:173–8.

    Article  PubMed  Google Scholar 

  39. Yombi JC, Putineanu DC, Cornu O, Lavand'homme P, Cornette P, Castanares-Zapatero D. Low haemoglobin at admission is associated with mortality after hip fractures in elderly patients. Bone Joint J. 2019;101-B:1122–8.

    Article  PubMed  Google Scholar 

  40. Suh YS, Nho JH, Seo J, Jang BW, Park JS. Hip fracture surgery without transfusion in patients with hemoglobin less than 10 g/dL. Clin Orthop Surg. 2021;13:30–6.

    Article  PubMed  Google Scholar 

  41. Aliberti S, Ramirez JA. Cardiac diseases complicating community-acquired pneumonia. Curr Opin Infect Dis. 2014;27:295–301.

    Article  CAS  PubMed  Google Scholar 

  42. Chou CY, Wang SM, Liang CC, Chang CT, Liu JH, Wang IK, et al. Risk of pneumonia among patients with chronic kidney disease in outpatient and inpatient settings: a nationwide population-based study. Medicine (Baltimore). 2014;93:e174.

    Article  Google Scholar 

  43. James MT, Quan H, Tonelli M, Manns BJ, Faris P, Laupland KB, et al. CKD and risk of hospitalization and death with pneumonia. Am J Kidney Dis. 2009;54:24–32.

    Article  PubMed  Google Scholar 

  44. Kim J, Park SJ, Choi S, Seo WW, Lee YJ. Hospitalization for acute coronary syndrome increases the long-term risk of pneumonia: a population-based cohort study. Sci Rep. 2021;11:9696.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Mor A, Thomsen RW, Ulrichsen SP, Sorensen HT. Chronic heart failure and risk of hospitalization with pneumonia: a population-based study. Eur J Intern Med. 2013;24:349–53.

    Article  PubMed  Google Scholar 

  46. Zhu J, Zhang X, Shi G, Yi K, Tan X. Atrial fibrillation is an independent risk factor for hospital-acquired pneumonia. Plos One. 2015;10:e0131782.

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  47. Hibberd J, Fraser J, Chapman C, McQueen H, Wilson A. Can we use influencing factors to predict aspiration pneumonia in the United Kingdom? Multidiscip Respir Med. 2013;8:39.

    Article  PubMed  PubMed Central  Google Scholar 

  48. Ding R, Logemann JA. Pneumonia in stroke patients: a retrospective study. Dysphagia. 2000;15:51–7.

    Article  CAS  PubMed  Google Scholar 

  49. O'Daly BJ, Walsh JC, Quinlan JF, Falk GA, Stapleton R, Quinlan WR, et al. Serum albumin and total lymphocyte count as predictors of outcome in hip fractures. Clin Nutr. 2010;29:89–93.

    Article  CAS  PubMed  Google Scholar 

  50. Bohl DD, Shen MR, Hannon CP, Fillingham YA, Darrith B, Della Valle CJ. Serum albumin predicts survival and postoperative course following surgery for geriatric hip fracture. J Bone Joint Surg Am. 2017;99:2110–8.

    Article  PubMed  Google Scholar 

  51. Ugajin M, Yamaki K, Iwamura N, Yagi T, Asano T. Blood urea nitrogen to serum albumin ratio independently predicts mortality and severity of community-acquired pneumonia. Int J Gen Med. 2012;5:583–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. Woodford-Williams E. Respiratory tract disease. Diagnosis and management of pneumonia in the aged. Br Med J. 1966;1:467–70.

    Article  CAS  PubMed Central  Google Scholar 

  53. Feng DY, Zhou YQ, Zou XL, Zhou M, Yang HL, Chen XX, et al. Elevated blood urea nitrogen-to-serum albumin ratio as a factor that negatively affects the mortality of patients with hospital-acquired pneumonia. Can J Infect Dis Med Microbiol. 2019;2019:1547405.

    Article  PubMed  PubMed Central  Google Scholar 

  54. Jinks MF, Kelly CA. The pattern and significance of abnormal liver function tests in community-acquired pneumonia. Eur J Intern Med. 2004;15:436–40.

    Article  CAS  PubMed  Google Scholar 

  55. Quinton LJ, Jones MR, Robson BE, Mizgerd JP. Mechanisms of the hepatic acute-phase response during bacterial pneumonia. Infect Immun. 2009;77:2417–26.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. Weber M, Lambeck S, Ding N, Henken S, Kohl M, Deigner HP, et al. Hepatic induction of cholesterol biosynthesis reflects a remote adaptive response to pneumococcal pneumonia. FASEB J. 2012;26:2424–36.

    Article  CAS  PubMed  Google Scholar 

  57. Novack V, Jotkowitz A, Etzion O, Porath A. Does delay in surgery after hip fracture lead to worse outcomes? A multicenter survey. Int J Qual Health Care. 2007;19:170–6.

    Article  PubMed  Google Scholar 

  58. Orosz GM, Magaziner J, Hannan EL, Morrison RS, Koval K, Gilbert M, et al. Association of timing of surgery for hip fracture and patient outcomes. JAMA. 2004;291:1738–43.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Radcliff TA, Henderson WG, Stoner TJ, Khuri SF, Dohm M, Hutt E. Patient risk factors, operative care, and outcomes among older community-dwelling male veterans with hip fracture. J Bone Joint Surg Am. 2008;90:34–42.

    Article  PubMed  Google Scholar 

  60. Siegmeth AW, Gurusamy K, Parker MJ. Delay to surgery prolongs hospital stay in patients with fractures of the proximal femur. J Bone Joint Surg Br. 2005;87:1123–6.

    Article  CAS  PubMed  Google Scholar 

  61. Simunovic N, Devereaux PJ, Sprague S, Guyatt GH, Schemitsch E, Debeer J, et al. Effect of early surgery after hip fracture on mortality and complications: systematic review and meta-analysis. CMAJ. 2010;182:1609–16.

    Article  PubMed  PubMed Central  Google Scholar 

  62. Smektala R, Endres HG, Dasch B, Maier C, Trampisch HJ, Bonnaire F, et al. The effect of time-to-surgery on outcome in elderly patients with proximal femoral fractures. BMC Musculoskelet Disord. 2008;9:171.

    Article  PubMed  PubMed Central  Google Scholar 

  63. Roberts KC, Brox WT, Jevsevar DS, Sevarino K. Management of hip fractures in the elderly. J Am Acad Orthop Surg. 3015;23:131–7.

    Article  Google Scholar 

Download references

Acknowledgements

None.

Funding

No funding source was applicable to any part of this study.

Author information

Authors and Affiliations

Authors

Contributions

KHS was the project leader and participated in all aspects of the study, including planning, design, literature search, data screening and extraction, quality appraisal, and management of all aspects of manuscript preparation and submission. SBH and SBK contributed to the study design, literature search, data screening and extraction, quality appraisal, and manuscript editing. All authors have read and approved the final manuscript.

Corresponding author

Correspondence to Kyun-Ho Shin.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no conflicts of interest.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Additional file 1.

Results of sensitive analysis for variables.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Han, SB., Kim, SB. & Shin, KH. Risk factors for postoperative pneumonia in patients undergoing hip fracture surgery: a systematic review and meta-analysis. BMC Musculoskelet Disord 23, 553 (2022). https://doi.org/10.1186/s12891-022-05497-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12891-022-05497-1

Keywords