Eight controlled trials (4,047 patients) were included: 4 RCTs (1,005 patients), 2 quasi-controlled trials (2,223 patients), one factorial study (727 patients) and one matched study (92 patients).
Arthritis (2 RCTs, 457 patients): both RCTs found a statistically- significant increase in patient knowledge scores with printed information in comparison with the control; the differences in knowledge scores between the groups were 14 and 15%. One RCT met one quality criterion while the other met two criteria.
Back pain (one RCT with 392 patients and one quasi-RCT with 1,872 patients): both trials found a statistically-significant increase in patient knowledge scores with printed information in comparison with the control. In the RCT, the difference in knowledge scores between the groups was 7%, while in the quasi-RCT, the OR of improvement in knowledge was 1.35. The increase in knowledge was maintained at 6 months in the RCT, but was not maintained in the quasi-RCT at 12 months. The RCT found no statistically-significant difference in provider visits for back pain, whereas the quasi-RCT found a significant reduction in provider visits among patients who received printed material compared with the control. The RCT met three quality criteria, while the quasi-RCT met one criterion.
Hypertension (one RCT with 156 patients, one quasi-RCT with 351 patients, one factorial study with 727 patients, one matched study with 92 patients): none of the studies found any significant difference, either in patient knowledge or adherence for printed material, compared with the control. The RCT met two quality criteria, the factorial study met one, and the other two studies did not meet any criteria.
All four trials of hypertensive patients were published in the early 1980s. Three of the four arthritis and back-pain trials were published in the mid-to-late 1990s.