Table 1 Results of the Joinpoint regression models for trend analysis of age-standardized prevalence and DALYs rates of knee osteoarthritis in China and the USA from 1990 to 2019

Trend 1

1990-2000

− 0.7 (− 0.9, − 0.4)^*

1990-2000

− 0.7 (− 0.9, − 0.4)^*

1990-2000

2.1 (1.8, 2.4)^*

Trend 2

2000-2005

2.5 (1.6, 3.5)^*

2000-2005

2.5 (1.6, 3.5)^*

2000-2005

6.0 (4.7, 7.2)^*

Trend 3

2005-2014

0.1 (−0.2, 0.4)

2005-2014

0.1 (−0.2, 0.5)

2005-2013

3.7 (3.2, 4.2)^*

Trend 4

2014-2019

−0.7 (− 1.4, − 0.0)^*

2014-2019

−0.7 (− 1.4, − 0.1)^*

2013-2019

2.0 (1.3, 2.6)^*

AAPC

1990-2019

0.1 (−0.1, 0.3)

1990-2019

0.1 (−0.1, 0.3)

1990-2019

3.2 (2.9, 3.5)^*

Trend 1

1990-2000

−0.4 (− 0.5, − 0.3)^*

1990-2000

−0.4 (− 0.4, − 0.3)^*

1990-1997

2.1 (1.8, 2.3)^*

Trend 2

2000-2005

1.9 (1.6, 2.2)^*

2000-2005

1.9 (1.6, 2.2)^*

1997-2009

4.1 (4.0, 4.2)^*

Trend 3

2005-2014

0.5 (0.4, 0.6)^*

2005-2014

0.6 (0.5, 0.7)^*

2009-2014

2.6 (2.0, 3.2)^*

Trend 4

2014-2019

−0.5 (−0.7, −0.3)^*

2014-2019

−0.6 (− 0.8, − 0.4)^*

2014-2019

1.7 (1.3, 2.1)^*

AAPC

1990-2019

0.3 (0.2, 0.3)^*

1990-2019

0.3 (0.2, 0.3)^*

1990-2019

2.9 (2.8, 3.1)^*

Trend 1

1990-1994

− 1.6 (− 2.7, −0.6)^*

1990-1994

−1.5 (− 2.5, − 0.5)^*

1990-2001

1.5 (1.3, 1.8)^*

Trend 2

1994-2001

0.3 (−0.3, 0.9)

1994-2001

0.3 (−0.3, 0.8)

2001-2005

−2.6 (−4.3, − 0.8)^*

Trend 3

2001-2004

−4.9 (−8.1, −1.7)^*

2001-2004

− 4.9 (− 8.0, − 1.8)^*

2005-2009

3.0 (1.2, 4.8)^*

Trend 4

2004-2019

0.9 (0.8, 1.1)^*

2004-2019

0.9 (0.8, 1.0)^*

2009-2019

1.0 (0.7, 1.2)^*

AAPC

1990-2019

−0.2 (−0.6, 0.2)

1990-2019

−0.2 (− 0.6, 0.2)

1990-2019

1.0 (0.6, 1.3)^*

Trend 1

1990-2000

0.4 (0.3, 0.6)^*

1990-2000

0.5 (0.3, 0.6)^*

1990-2000

1.5 (1.3, 1.6)^*

Trend 2

2000-2005

−3.3 (−4.0, −2.7)^*

2000-2005

−3.4 (− 4.0, − 2.8)^*

2000-2005

−2.7 (−3.2, − 2.1)^*

Trend 3

2005-2009

1.7 (0.6, 2.8)^*

2005-2009

1.7 (0.6, 2.7)^*

2005-2009

2.3 (1.4, 3.1)^*

Trend 4

2009-2019

0.6 (0.5, 0.8)^*

2009-2019

0.6 (0.4, 0.7)^*

2009-2019

0.8 (0.7, 0.9)^*

AAPC

1990-2019

0.0 (−0.2, 0.2)

1990-2019

−0.0 (− 0.2, 0.2)

1990-2019

0.6 (0.5, 0.8)^*