Table 2.

2012 Utilization of Healthcare Resources by Nurses' Health Study Participants and Matched Medicare Beneficiaries

Utilization category	NHS participants (N = 47,194)	Matched Medicare cohort (N = 47,194)	p-Value	Total difference in utilizationa(95% CI)	Relative differencebin utilization (%)
Preventive testing (percentage of women undergoing a test in 2012)
Mammogram	53.2 (52.8–53.7)	43.8 (43.3–44.2)	<0.01	9.5 (8.8–10.1)	22
Colonoscopy	7.8 (7.5–8.0)	7.0 (6.8–7.2)	<0.01	0.8 (0.4–1.1)	11
Flexible sigmoidoscopy	0.4 (0.3–0.5)	0.4 (0.3–0.4)	0.43	0.0 (0.0–0.1)	9
Barium enema	0.2 (0.2–0.3)	0.2 (0.2–0.3)	0.89	0.0 (−0.1 to 0.1)	−2
Fecal occult blood testing	1.8 (1.7–1.9)	1.6 (1.5–1.8)	0.10	0.1 (0.0–0.3)	8
DEXA bone densitometry	17.3 (16.9–17.6)	14.7 (14.4–15.0)	<0.01	2.6 (2.1–3.0)	17
Outpatient service rates (per capita)
ER visitsc	1.1 (1.1–1.1)	1.1 (1.1–1.1)	<0.01	−0.02 (−0.03 to 0.01)	−2
Primary care E/Md visits	3.8 (3.8–3.9)	3.9 (3.8–3.9)	0.16	0.0 (−0.1 to 0.0)	−1
Specialty care E/M visits	5.6 (5.5–5.6)	4.9 (4.8–4.9)	<0.01	0.7 (0.6–0.8)	14
Total E/M visits	9.4 (9.3–9.5)	8.7 (8.7–8.8)	<0.01	0.7 (0.6–0.8)	7
Inpatient service rates (per 1,000)
Medical discharges	191 (186–197)	175 (169–180)	<0.01	17 (9–24)	10
Surgical discharges	89 (87–92)	72 (70–75)	<0.01	17 (13–21)	24
Total discharges	281 (274–288)	247 (241–253)	<0.01	34 (25–43)	14

^aThe total difference in utilization is calculated as follows: (Utilization by NHS participants) – (Utilization by matched Medicare cohort). Negative numbers indicate less utilization by NHS participants than Medicare controls.

^bRelative difference in utilization is calculated: (Total difference in utilization)/(Utilization by NHS participants). Negative numbers indicate less utilization by NHS participants than Medicare controls.

^cER visits not leading to inpatient admission.

^dEvaluation and management.

CI, confidence interval; DEXA, dual-energy x-ray absorptiometry; E/M, evaluation and management; ER, emergency room.