Validation of Administrative Osteoarthritis Diagnosis Using a Clinical and Radiological Population-Based Cohort

Table 1

Percentage of knee, hand, and hip osteoarthritis (OA) by each reference standard, knee OA assessment, and other baseline characteristics of 171 subjects who underwent comprehensive clinical assessment for knee OA by sex.

Characteristics	Women%	Men%	value
Reference standards
RS1	77.4	57.5	<0.01
RS2	82.1	56.3	<0.01
RS3	96.4	89.7	0.08
RS4	84.5	62.1	<0.01
Knee OA assessment
Clinical ACR criteria	48.8	40.2	0.26
K-L grade ≥ 2	42.9	44.9	0.79
MRI cartilage score ≥ 2	91.7	88.5	0.48
Self-report	50.0	48.3	0.82
Other characteristics
Age in years			0.44
40–49	14.3	21.8
50–64	51.2	46.0
65–79	34.5	32.2
Body mass index (kg/m^2)			0.02
18.5–24.9	46.3	28.7
25.0–29.9	27.4	46.0
30+	26.2	25.3
Hip pain	42.9	18.4	<0.01
Symptomatic hand OA	43.4	18.4	<0.01

RS1, RS2, RS3, and RS4 are four reference standards including knee, hand, and hip OA which are described in Methods.
K-L = Kellgren-Lawrence, self-report = self-reported physician diagnosed knee OA, MRI = magnetic resonance imaging, and ACR = American College of Rheumatology.