Houten, Holly K. Van

OBJECTIVE Hypoglycemia is a cause of significant morbidity among patients with diabetes and may be associated with greater risk of death. We conducted a retrospective study to determine whether patient self-report of severe hypoglycemia is associated with increased mortality. RESEARCH DESIGN AND METHODS Adult patients (N = 1,020) seen in a specialty diabetes clinic between August 2005 and July 2006 were questioned about frequency of hypoglycemia during a preencounter interview; 7 were lost to follow-up and excluded from analysis. Mild hypoglycemia was defined as symptoms managed without assistance, and severe hypoglycemia was defined as symptoms requiring external assistance. Mortality data, demographics, clinical characteristics, and Charlson comorbidity index (CCI) were obtained from the electronic medical record after 5 years. Patients were stratified by self-report of hypoglycemia at baseline, demographics were compared using the two-sample t test, and risk of death was expressed as odds ratio (95% CI). Associations were controlled for age, sex, diabetes type and duration, CCI, HbA1c, and report of severe hypoglycemia. RESULTS In total, 1,013 patients with type 1 (21.3%) and type 2 (78.7%) diabetes were questioned about hypoglycemia. Among these, 625 (61.7%) reported any hypoglycemia, and 76 (7.5%) reported severe hypoglycemia. After 5 years, patients who reported severe hypoglycemia had 3.4-fold higher mortality (95% CI 1.5–7.4; P = 0.005) compared with those who reported mild/no hypoglycemia. CONCLUSIONS Self-report of severe hypoglycemia is associated with 3.4-fold increased risk of death. Patient-reported outcomes, including patient-reported hypoglycemia, may therefore augment risk stratification and disease management of patients with diabetes.

Surveys of physicians are an important tool to assess opinions and self-reported behaviors of this policy-relevant population. However, this population is notoriously difficult to survey and plagued with low and falling response rates. In order to evaluate the potential import of response rate, we examine the presence of nonresponse bias in a survey of physicians providing diabetes care that achieved a 36% response rate. Unlike other studies examining differences in individual characteristics for responding and nonresponding physicians, we also assess differences with respect to aggregate patient demographic, clinical, and behavioral characteristics. We are unable to demonstrate nonresponse bias, even with what could be construed as a relative low response rate. Nonetheless as the threat of nonresponse bias can never be completely assuaged, we believe that it should be monitored as a matter of course in physician surveys and offer a new dimension by which it can be evaluated.