Relationship between patient-reported disease severity and other clinical outcomes in osteoarthritis: a European perspective

Figures & data

Table 1.  Demographic characteristics of the population evaluated in the European osteoarthritis Disease Specific Program (N = 1739).

Variable (number of observations)	Value*
Country, % (n = 1739)
France	15.4
Germany	29.7
Italy	15.1
Spain	29.3
UK	14.8
Mean age ± SD, years (n = 1739)	64.4 ± 11.9
Age range, % (n = 1739)
18–44 years	5.6
45–64 years	41.3
≥65 years	53.0
Gender, % (n = 1739)
Female	63.1
Male	36.9
Mean body mass index ± SD, kg/m^2
Women (n = 1059)	28.1 ± 11.9
Men (n = 609)	27.5 ± 13.1
Employment, % (n = 1630)
Full time	21.8
Part time	4.1
Unemployed	3.7
Retired	51.2
Student	0.1
Homemaker	18.2
Other	0.9
Mean time since diagnosis ± SD, years (n = 1579)	5.0 ± 5.6

*Values and proportions are based on observed cases (i.e., number of subjects who supplied data for each variable).

Table 2.  Physician-reported versus patient-reported osteoarthritis severity; 1 = mild, 2 = moderate, 3 = severe (weighted kappa coefficient = 0.61; 95% confidence interval = 0.57–0.64).

Physician-reported severity		Patient-reported severity			Row total, n (%)
		Mild	Moderate	Severe
Mild	Frequency	312	178	19	509 (29.6)
Moderate	Frequency	102	741	140	983 (57.1)
Severe	Frequency	5	54	170	229 (13.3)
Column total, n (%)		419 (24.4)	973 (56.5)	329 (19.1)	1721 (100)

Figure 1.  Relationship between self-reported osteoarthritis severity and age.

Table 3.  Relationship between self-reported osteoarthritis (OA) severity and functional ability to perform activities of daily living.

Functional measure	Functional score at each level of OA severity (95% confidence interval)*
	Mild	Moderate	Severe
Basic activities of daily living
Dressing, including shoelaces and buttons	1.30 (1.24, 1.36)	1.67 (1.63, 1.71)	2.14 (20.8, 2.21)
Washing hair	1.29 (1.22, 1.36)	1.55 (1.50, 1.59)	1.95 (1.87, 2.02)
Rising from chair	1.37 (1.31, 1.43)	1.70 (1.67, 1.74)	2.25 (2.19, 2.32)
Getting in and out of bed	1.34 (1.28, 1.40)	1.71 (1.67, 1.75)	2.25 (2.18, 2.31)
Walking on flat ground	1.31 (1.25, 1.37)	1.65 (1.61, 1.69)	2.23 (2.17, 2.30)
Climbing 5 steps	1.53 (1.46, 1.59)	1.96 (1.92, 2.01)	2.60 (1.53, 2.68)
Washing and drying	1.23 (1.17, 1.29)	1.48 (1.44, 1.52)	1.91 (1.85, 1.98)
Taking a bath	1.45 (1.38, 1.52)	1.81 (1.76, 1.86)	2.40 (2.32, 2.48)
Toileting	1.27 (1.22, 1.33)	1.58 (1.54, 1.62)	2.07 (2.00, 2.13)
Instrumental activities of daily living
Shopping	1.38 (1.31, 1.45)	1.76 (1.71, 1.80)	2.43 (2.36, 2.51)
Getting in and out of a car	1.40 (1.33, 1.46)	1.79 (1.75, 1.83)	2.34 (2.27, 2.41)
Performing chores (e.g. vacuuming or gardening)	1.61 (1.53, 1.68)	2.06 (2.02, 2.11)	2.85 (2.77, 2.94)

Response options: 1 – without any difficulty, 2 – with some difficulty, 3 – with much difficulty, 4 – unable to do.

*All pair-wise comparisons of severity categories were statistically significant (p < 0.05).

Figure 2.  Relationship between patient-rated osteoarthritis severity and patient-reported productivity. Evaluation of productivity based on the Work Productivity and Activity Impairment (WPAI) questionnaire30. CI, confidence interval. Values of means of percent impairment were adjusted for age, gender and country. *p < 0.05 for pair-wise comparisons between severity levels.

Figure 3.  Relationship between patient-reported osteoarthritis (OA) severity and components of the EQ-5D including (A) the five dimensions of the EQ-5D; (B) the EQ-5D current health state thermometer (0–100 visual analogue scale [VAS]; and (C) the EQ-5D index based on the UK value set. Values are means, adjusted for age, gender and country, with 95% confidence intervals. All pair-wise comparisons on OA severity were statistically significant (p < 0.0001).

Figure 4.  Relationship between patient-reported osteoarthritis (OA) severity and physician-reported clinical parameters of (A) radiologic deterioration in joint space (p < 0.001 for overall association) (B) joint deformity (mean levels; 1 = mild, 2 = moderate, 3 = severe; p < 0.05 for all pair-wise comparisons between severity levels, adjusted for age, gender and country) and (C) disease progression (p < 0.001 for overall association).

Reilly, Margaret C., Zbrozek, Arthur S., Dukes, Ellen M. The validity and reproducibility of a work productivity and activity impairment instrument. Pharmacoeconomics 1993;4:353-65

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