Table 1.

Characteristics of disease risk score confounder summary method applications, N=86

			Year of Publication
	Total (n=86)		<2000 (n=47)		≥2000 (n=39)
	No.	%	No.	%	No.	%
Area of Study
Drug effects	21	24.4	3	6.4	18	46.2
Environmental and social exposure/disease	18	20.9	15	31.9	3	7.7
Hospital Care/Health Care	10	11.6	8	17.0	2	5.1
Cancer Risk	23	26.7	9	19.1	14	35.9
Skin Cancer Risk	15	17.4	1	2.1	14	35.9
Pregnancy outcomes	8	9.3	7	14.9	1	2.6
Surgical effectiveness	4	4.7	3	6.4	1	2.6
Ophthalmology	2	2.3	2	4.3	0	0.0
Study Design
Cohort	40	46.5	19	40.4	21	53.8
Case-Control	36	41.9	23	48.9	13	33.3
Cross-sectional	5	5.8	3	6.4	2	5.1
Clinical Trial	5	5.8	2	4.3	3	7.7
DRS Derivation (Regression Method)
Not Reported	9	10.5	6	12.8	3	7.7
Reported	77	89.5	41	87.2	36	92.3
Logistic	36	46.8	15	36.6	21	58.3
Discriminant	13	16.9	13	31.7	0	0.0
Linear	8	10.4	8	19.5	0	0.0
Poisson	7	9.1	0	0.0	7	19.4
Cox Proportional Hazards	6	7.8	1	2.4	5	13.9
Other	7	9.1	4	9.8	3	8.3
Primary DRS Application Method
Not Reported	3	3.5	2	4.3	1	2.6
Reported	83	96.5	45	95.7	38	97.4
Stratification	50	60.2	40	88.9	10	26.3
Included as covariate	29	34.9	5	11.1	24	63.2
Matching	2	2.4	0	0.0	2	5.3
Other	2	2.4	0	0.0	2	5.3
Primary DRS Application Variable
Not Reported	13	15.1	10	21.3	3	7.7
Reported	73	84.9	37	78.7	36	92.3
Continuous	5	6.8	2	5.4	3	8.3
Categorical*	68	93.2	35	94.6	33	91.7
2	4	5.9	1	2.8	3	9.1
3	19	27.9	8	22.8	11	33.3
4	13	19.1	7	20.0	6	18.2
5	19	27.9	16	45.7	3	9.1
10	12	17.6	3	8.6	9	27.3
20	2	2.9	0	0.0	2	6.0
Other	5	7.3	4	11.4	1	3.0

^*Some applications examined several categories and thus proportions add to greater than 100%