Recruitment to a Clinical Trial Improves Glycemic Control
Recruitment to a Clinical Trial Improves Glycemic Control
Objective: We assessed the effect upon A1C of recruitment to a clinical trial in patients with diabetes who had been screened and interviewed to determine eligibility but whose therapy was otherwise unchanged.
Research Design and Methods: Eligible trials were selected from the global program of an insulin manufacturer. Included were studies in which patients were seen on a single screening visit, pharmaceutical therapy was not altered before randomization, and A1C was measured in a central laboratory at both screening and randomization. Three trials involving patients with type 1 diabetes (n = 429) and three trials involving patients with type 2 diabetes (n = 611) were identified for analysis. The main outcome measure was change in A1C. Separate regression equations on the change in A1C were fitted for type 1 and type 2 diabetes and included effects of baseline A1C and the interval between the screening and randomization visits.
Results: A1C changed by -0.13% (range +0.09 to -0.26%) in those with type 1 diabetes at a median of 28 days and by -0.16% (-0.14 to -0.27%) for those with type 2 diabetes at a median of 14 days. The mean change in A1C in those with an interval of ≥28 days was -0.24% for those with type 1 diabetes and -0.23% for those with type 2 diabetes. The reduction was proportional to initial A1C, with large decreases in those with the poorest initial control but no overall change in those at or below the 10th percentile of A1C.
Conclusions: Recruitment to a clinical trial, independent of any therapeutic intervention, produces improvements in glucose control.
Diabetes management centers on the patient, who assumes direct responsibility for all aspects of his or her care. This includes day-to-day management of finger-stick glucose measurements, diet, exercise, and glucose-lowering medications (oral tablets and/or insulin injections). Successful integration of these variables is demanding and requires unremitting attention. Behavioral interventions have been shown to improve glucose control, but it is not easy to distinguish between the specific benefit of such interventions and the nonspecific effects of study participation, which include increased patient attention and motivation. There is some evidence that patients' glycemic control will benefit simply from participation in a clinical study.
We wanted to estimate the influence of study participation on glucose control by retrospective analysis of the effect of the single screening visit that precedes allocation to treatment in a clinical trial. Patients potentially eligible for such trials meet a study representative, usually the study nurse. In the course of this visit, the nature of the study is explained, written consent to participation is obtained, and baseline clinical and laboratory measurements are made. Advice about aspects of management, such as blood glucose monitoring, may also be offered. No other intervention was offered in the trials we considered. Eligibility having been confirmed, the patient is brought back on a second occasion and randomized to new therapy. We set out to analyze the difference in glycemic control, as measured by A1C, between the two visits. Since the analysis was retrospective, the patients and clinical teams participating in these trials were unaware that differences in glucose control might be considered over the period between screening and randomization, thus allowing us to examine the influence of recruitment to a clinical trial upon glycemic control in isolation from any change in therapy.
Objective: We assessed the effect upon A1C of recruitment to a clinical trial in patients with diabetes who had been screened and interviewed to determine eligibility but whose therapy was otherwise unchanged.
Research Design and Methods: Eligible trials were selected from the global program of an insulin manufacturer. Included were studies in which patients were seen on a single screening visit, pharmaceutical therapy was not altered before randomization, and A1C was measured in a central laboratory at both screening and randomization. Three trials involving patients with type 1 diabetes (n = 429) and three trials involving patients with type 2 diabetes (n = 611) were identified for analysis. The main outcome measure was change in A1C. Separate regression equations on the change in A1C were fitted for type 1 and type 2 diabetes and included effects of baseline A1C and the interval between the screening and randomization visits.
Results: A1C changed by -0.13% (range +0.09 to -0.26%) in those with type 1 diabetes at a median of 28 days and by -0.16% (-0.14 to -0.27%) for those with type 2 diabetes at a median of 14 days. The mean change in A1C in those with an interval of ≥28 days was -0.24% for those with type 1 diabetes and -0.23% for those with type 2 diabetes. The reduction was proportional to initial A1C, with large decreases in those with the poorest initial control but no overall change in those at or below the 10th percentile of A1C.
Conclusions: Recruitment to a clinical trial, independent of any therapeutic intervention, produces improvements in glucose control.
Diabetes management centers on the patient, who assumes direct responsibility for all aspects of his or her care. This includes day-to-day management of finger-stick glucose measurements, diet, exercise, and glucose-lowering medications (oral tablets and/or insulin injections). Successful integration of these variables is demanding and requires unremitting attention. Behavioral interventions have been shown to improve glucose control, but it is not easy to distinguish between the specific benefit of such interventions and the nonspecific effects of study participation, which include increased patient attention and motivation. There is some evidence that patients' glycemic control will benefit simply from participation in a clinical study.
We wanted to estimate the influence of study participation on glucose control by retrospective analysis of the effect of the single screening visit that precedes allocation to treatment in a clinical trial. Patients potentially eligible for such trials meet a study representative, usually the study nurse. In the course of this visit, the nature of the study is explained, written consent to participation is obtained, and baseline clinical and laboratory measurements are made. Advice about aspects of management, such as blood glucose monitoring, may also be offered. No other intervention was offered in the trials we considered. Eligibility having been confirmed, the patient is brought back on a second occasion and randomized to new therapy. We set out to analyze the difference in glycemic control, as measured by A1C, between the two visits. Since the analysis was retrospective, the patients and clinical teams participating in these trials were unaware that differences in glucose control might be considered over the period between screening and randomization, thus allowing us to examine the influence of recruitment to a clinical trial upon glycemic control in isolation from any change in therapy.
