Association of lumbar disc degeneration with low back pain in middle age in the Northern Finland Birth Cohort 1966

Table 2 Inter-rater reliability in the Pfirrmann classification. Weighted Kappa values (κ) with 95% confidence intervals (95% CI) by lumbar level (n = 50 cases in each comparison)

Lumbar level	Reader #1 (J.K.) vs. Reader #2 (J.N.)		Reader #1 (J.K.) vs. Reader #3 (R.B.)		Reader #2 (J.N.) vs. Reader #3 (R.B.)
Lumbar level	κ	95% CI	κ	95% CI	κ	95% CI
L1/L2	0.78	0.63–0.93	0.41	0.19–0.62	0.69	0.51–0.88
L2/L3	0.76	0.62–0.91	0.39	0.19–0.59	0.61	0.42–0.79
L3/L4	0.75	0.60–0.91	0.58	0.39–0.76	0.79	0.64–0.94
L4/L5	0.77	0.64–0.90	0.69	0.55–0.83	0.64	0.49–0.80
L5/S1	0.74	0.62–0.86	0.63	0.50–0.76	0.65	0.51–0.79

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