Table 2.

Rate ratios for OA diagnosis among patients with an incident primary total knee replacement between 2000 and 2015

	Clinical OA		Diagnosed OA		Knee OA
	3-year	10-year	3-year	10-year	3-year	10-year
	Unadjusted rate ratios
2000	Reference	Reference	Reference	Reference	Reference	Reference
2001	0.991 (0.888–1.105)	0.989 (0.889–1.100)	0.956 (0.836–1.092)	0.971 (0.856–1.102)	0.904 (0.750–1.090)	0.920 (0.778–1.087)
2002	0.984 (0.885–1.094)	0.974 (0.878–1.080)	0.942 (0.828–1.072)	0.962 (0.852–1.088)	0.925 (0.774–1.107)	0.944 (0.804–1.108)
2003	0.977 (0.882–1.082)	0.970 (0.878–1.072)	0.904 (0.797–1.025)	0.905 (0.803–1.020)	0.872 (0.733–1.039)	0.838 (0.716–0.982)
2004	0.987 (0.893–1.090)	0.978 (0.887–1.078)	0.896 (0.792–1.012)	0.901 (0.802–1.012)	0.893 (0.754–1.058)	0.863 (0.741–1.006)
2005	0.998 (0.906–1.100)	0.982 (0.893–1.080)	0.895 (0.795–1.009)	0.914 (0.816–1.023)	0.907 (0.769–1.069)	0.886 (0.764–1.028)
2006	0.987 (0.896–1.088)	0.973 (0.885–1.070)	0.856 (0.759–0.964)	0.888 (0.793–0.994)	0.894 (0.759–1.054)	0.849 (0.731–0.985)
2007	1.010 (0.919–1.110)	0.990 (0.902–1.086)	0.862 (0.767–0.969)	0.889 (0.796–0.993)	0.868 (0.739–1.020)	0.811 (0.701–0.939)
2008	0.976 (0.889–1.071)	0.961 (0.878–1.053)	0.777 (0.692–0.872)	0.826 (0.740–0.921)	0.819 (0.699–0.960)	0.783 (0.678–0.903)
2009	0.963 (0.878–1.057)	0.947 (0.865–1.036)	0.732 (0.653–0.821)	0.782 (0.702–0.872)	0.766 (0.654–0.898)	0.725 (0.629–0.837)
2010	0.954 (0.871–1.046)	0.941 (0.861–1.029)	0.674 (0.601–0.755)	0.727 (0.653–0.810)	0.705 (0.602–0.824)	0.672 (0.583–0.774)
2011	0.931 (0.850–1.021)	0.923 (0.844–1.010)	0.618 (0.551–0.693)	0.684 (0.614–0.762)	0.688 (0.588–0.805)	0.668 (0.580–0.770)
2012	0.916 (0.836–1.004)	0.919 (0.841–1.005)	0.620 (0.553–0.695)	0.690 (0.620–0.769)	0.679 (0.580–0.794)	0.663 (0.576–0.764)
2013	0.887 (0.809–0.973)	0.891 (0.815–0.975)	0.560 (0.499–0.629)	0.651 (0.584–0.725)	0.621 (0.530–0.728)	0.628 (0.545–0.724)
2014	0.873 (0.796–0.958)	0.882 (0.806–0.965)	0.528 (0.470–0.594)	0.621 (0.557–0.693)	0.589 (0.502–0.691)	0.619 (0.536–0.714)
2015	0.835 (0.755–0.924)	0.858 (0.778–0.946)	0.481 (0.421–0.551)	0.587 (0.518–0.664)	0.548 (0.457–0.657)	0.579 (0.493–0.681)
	Adjusted rate ratiosa
2000	Reference	Reference	Reference	Reference	Reference	Reference
2001	0.991 (0.893–1.099)	0.989 (0.894–1.094)	0.955 (0.842–1.084)	0.971 (0.861–1.095)	0.903 (0.757–1.078)	0.919 (0.784–1.077)
2002	0.984 (0.890–1.088)	0.974 (0.883–1.074)	0.942 (0.833–1.065)	0.962 (0.856–1.081)	0.925 (0.780–1.096)	0.943 (0.810–1.099)
2003	0.977 (0.887–1.077)	0.969 (0.882–1.066)	0.903 (0.801–1.017)	0.904 (0.807–1.012)	0.871 (0.738–1.028)	0.837 (0.720–0.972)
2004	0.986 (0.897–1.084)	0.978 (0.891–1.072)	0.895 (0.796–1.005)	0.900 (0.806–1.005)	0.892 (0.760–1.048)	0.862 (0.745–0.997)
2005	0.998 (0.910–1.094)	0.982 (0.897–1.075)	0.894 (0.799–1.002)	0.913 (0.820–1.017)	0.906 (0.775–1.060)	0.885 (0.769–1.019)
2006	0.987 (0.900–1.082)	0.973 (0.889–1.064)	0.854 (0.763–0.957)	0.887 (0.797–0.988)	0.893 (0.764–1.044)	0.847 (0.736–0.976)
2007	1.010 (0.923–1.105)	0.990 (0.907–1.081)	0.861 (0.771–0.962)	0.888 (0.799–0.986)	0.867 (0.744–1.010)	0.810 (0.705–0.930)
2008	0.976 (0.893–1.066)	0.961 (0.881–1.048)	0.775 (0.694–0.865)	0.824 (0.743–0.914)	0.817 (0.703–0.950)	0.781 (0.681–0.895)
2009	0.963 (0.882–1.051)	0.946 (0.869–1.031)	0.730 (0.654–0.814)	0.780 (0.704–0.865)	0.764 (0.658–0.888)	0.723 (0.631–0.828)
2010	0.954 (0.874–1.040)	0.940 (0.864–1.024)	0.671 (0.602–0.748)	0.725 (0.654–0.803)	0.702 (0.605–0.815)	0.669 (0.585–0.766)
2011	0.931 (0.853–1.015)	0.922 (0.847–1.004)	0.615 (0.552–0.686)	0.681 (0.615–0.755)	0.685 (0.590–0.796)	0.665 (0.582–0.761)
2012	0.915 (0.839–0.998)	0.918 (0.844–0.999)	0.617 (0.553–0.687)	0.688 (0.621–0.762)	0.676 (0.583–0.785)	0.661 (0.578–0.755)
2013	0.886 (0.812–0.967)	0.890 (0.818–0.969)	0.557 (0.499–0.622)	0.648 (0.584–0.718)	0.618 (0.532–0.719)	0.625 (0.546–0.716)
2014	0.872 (0.799–0.952)	0.881 (0.808–0.959)	0.525 (0.469–0.586)	0.618 (0.557–0.686)	0.586 (0.503–0.682)	0.616 (0.538–0.706)
2015	0.834 (0.758–0.918)	0.857 (0.780–0.940)	0.478 (0.420–0.543)	0.583 (0.519–0.656)	0.545 (0.458–0.648)	0.576 (0.494–0.672)

Notes: Proportion of OA diagnosis in 2000 was used as reference group. Estimations derived from 3- and 10-year run-in period methods were presented.

^aAge and sex were adjusted.

Abbreviation: OA, osteoarthritis.