The number of FPs at each stage of the trial is shown in . One hundred and seven FPs in 66 practices completed the trial. compares their baseline data across the intervention groups. During the trial, 19,187 individual patients aged 50+ years visited an FP at least once. Of these, 5,628 were eligible for screening for diabetes. The percentage screened in each group were: computer 31.8%, patient 23.9%, both 23.7%, and usual 15.5%. Computer reminders were more effective than patient reminders (odds ratio [OR] 1.49, 95% confidence interval [CI] 1.07, 2.07). The usual group screening rate was close to that for all groups combined in the 2 months prior to the trial (15.7%, P .80).
FIGURE 2 Flow diagram of family practitioner (FP) numbers in trial. *Not using MedTech 32 (474), not having electronic laboratory results for ≥1 year (75), not recording clinical notes on computer (32), not in Auckland (5), not an FP (9), 1 entry each (more ...)
Comparative Data for FPs, Practices, and Patients by Intervention Group
A Model to Predict Screening of Eligible Patients
Family practitioner, practice, and patient items that were common to all intervention groups were considered for a model predicting screening across all patients in the trial, shown in . This model was manually refined to include only those items that, in combination, each retained a significance P<.05 apart from non-European ethnicity, which was retained because of its plausibility in the New Zealand context; see .
Odds Ratio for Eligible Patients Being Screened, All Variables Initially Considered Likely to Predict Screening*
Odds Ratio (OR) for Eligible Patients Being Screened, Showing Contribution of Key Variables
The reminders increased glucose testing for both patients who were defined as eligible for screening and, to a lesser extent, those who were not. For example, comparing the computer group with the usual group, the OR for eligible patients being screened was 2.55 (P<.001) and for those who were not eligible was 1.31 (P .04).
Patient Sheet Analysis
There were 1,883 patient reminder sheets returned from 28 practices. The number of sheets per practice ranged from 0 to 262. It seemed possible that patient reminders—when delivered—were highly effective, but that the measured effect was minimized in the previous intention-to-treat analyses. Logistic regression comparing practices that returned patient sheets from more or less than 25% (approximately the mean) of their eligible patients showed no statistically significant difference, but practice numbers were relatively small.
Examining the Low Screening Rate with Both Reminders
There was no statistically significant difference between the proportion of sheets delivered to patients in the both reminders group (mean 0.30, SE 0.12) and in the patient reminders group (mean 0.23, SE 0.10), P .65.
The data were examined to see whether the both reminders group, in comparison with either the patient or computer reminders groups, had smaller numbers of patients who visited more often, were regular, or were non-European patients, or whether the FPs had lower rates of screening prior to the trial. For the first 3 variables, the figures given are percentages of patients in each group with significance testing using clustered logistic regression for odds of being screened. Prior screening rates were tested as proportions between groups of FPs. Compared with the computer group, the both reminders group had a smaller proportion of regular patients (77% vs 79%, OR 2.46, SE 0.50, CI 1.65, 3.66), no statistically significant difference in the proportion of non-European patients (27% vs 36%, OR 1.11, SE 0.19, CI 0.80, 1.54), or in FP prior screening rate (20% SE 7% vs 21% SE 8%, P .95) but a higher mean number of visits per patient during the trial (1.54 vs 1.45, OR 1.22, SE 0.05, CI 1.11, 1.32). Compared with the patient group, the both reminders group had a smaller proportion of regular patients (77% vs 85%, OR 3.14, SE 0.58, CI 2.18, 4.52), no statistically significant difference in proportion of non-European patients (27% vs 18%, OR 1.10, SE 0.18, CI 0.80, 1.51) or FP prior screening rate (20% SE 7% vs 15% SE 7%, P .65), but higher mean number of patient visits during the trial (1.54 vs 1.53, OR 1.23, SE 0.05, CI 1.14, 1.33).