Table V.

Health care use over the 6-year follow-up period for the matched OAI sample (N = 570)

Characteristic	Mild, non-progressive N = 235	Moderate (A) (intercept = 4.8) N = 139	Moderate (B) (intercept = 6.9) N = 106	Moderate (C) (intercept = 9.9) N = 64	Severe, non-improving N = 26
Age∗	64 (8.5)	64 (8.3)	64 (8.6)	64 (9.0)	59 (6.9)
Female gender N (%)	111 (47)	65 (47)	61 (58)	39 (61)	20 (77)
Knee function
Baseline WOMAC function27,†	4.0 (0.0, 13.0)	20.0 (12.0, 26.0)	25.3 (19.0, 34.0)	35.5 (29.4, 41.0)	41.7 (37.0, 48.9)
Health care use
Total knee arthroplasty received during 6-yr follow-up period	1 (0)	6 (4)	12 (11)	5 (8)	1 (4)
Average‡ treatment use prevalence over the seven study time points (%)
Paracetamol (Tylenol, acetaminophen)	6%	12%	19%	25%	29%
NSAIDS	18%	30%	31%	35%	53%
COXIBS (e.g., Bextra, Celebrex)	2%	5%	7%	5%	6%
Strong prescription pain medication (e.g., Narcotics)	2%	4%	7%	12%	14%

Figures are numbers and percentages unless otherwise stated.

^∗Mean (standard deviation).

^†Median (interquartile range).

^‡Average treatment prevalence is a weighted mean with $wi=Ni/{\sum }_{\text{i}=1}^{7}Ni\text{and}AP={\sum }_{\text{i}=1}^{7}wi\times p_i$ where w = weight, i = time point, N = number of participants without missing data, AP = average prevalence and p = prevalence of treatment use.