Effects of Strategy on the Mean (SD) Number of Tests and the Coefficient of Variance, per Primary Care Physician and per 6 Months
| Intervention Arm | Feedback Arm | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Study Subjects | Baseline Mean (SD) | CV* | Follow-up Mean (SD) | CV* | Baseline Mean (SD) | CV* | Follow-up Mean (SD) | CV* | β† | SE β | 95% CI | P |
| Note: analysis of covariance adjusted for baseline number of tests and the regions. | ||||||||||||
| CV = coefficient of variance; CI = confidence interval. | ||||||||||||
| * CV = SD / mean. | ||||||||||||
| † β = intervention effect = the total change between baseline and follow-up of mean numbers of tests in Intervention arm less the total change of numbers between baseline and follow-up of mean numbers of tests in the feedback arm. | ||||||||||||
| Total number of tests | 478 (309) | 0.65 | 422 (235) | 0.56 | 541 (337) | 0.62 | 535 (309) | 0.58 | −51 | 17.94 | −87 to −16 | .005 |
| Cardiovascular conditions | 293 (189) | 0.65 | 276 (157) | 0.57 | 322 (214) | 0.66 | 333 (205) | 0.62 | −25 | 13.08 | −51 to 1 | .056 |
| Lower abdominal complaints | 20 (20) | 1.00 | 18 (19) | 1.06 | 30 (40) | 1.43 | 30 (27) | 0.90 | −6 | 2.18 | −10 to −2 | .008 |
| Upper abdominal complaints | 165 (125) | 0.76 | 128 (82) | 0.64 | 188 (143) | 0.76 | 171(117) | 0.68 | −24 | 7.98 | −40 to −8 | .003 |
| Inappropriate upper abdominal tests | 55 (60) | 1.09 | 39 (32) | 0.82 | 60 (63) | 1.05 | 56 (54) | 0.96 | −13 | 4.1 | −22 to −5.2 | .002 |