Prevalence, Care, and Outcomes for Patients with Diet-Controlled Diabetes in General Practice: Cross-Sectional Survey

Hippisley-Cox J, Pringle M. Lancet. 2004;363:423-428.

The objective of this cross-sectional population-based study of patients with type 2 diabetes was to determine whether complications from lack of glycemic control were more prevalent in patients treated with diet alone or with hypoglycemic medication. Another objective was to compare quality of care of these treatment approaches. The study sampled 7870 patients from 42 general practices in the UK, considered demographically representative of the general population. The primary end points were diabetes-related complications and quality of diabetes care. There were 2700 patients in the diet-treated group with mean age of diabetes onset of 58 years and 5170 patients in the medication-treated group with an average age of diabetes onset of 60 years. Complications included in the comparison were vascular disease, evidence of diabetes-related eye disorders, evidence of neuropathy, amputation or leg ulcer, and evidence of renal disease.

A surprising finding was that almost one-third (31.3%) of patients were being managed without medication (defined as 1 or more prescriptions of hypoglycemics within the past 6 months). The percentage of diet-treated patients varied substantially (almost four-fold) among practices—ranging from 15.6% to 73.2% of patients in the practices. Examination of the electronic records for both groups revealed that across-practices, diet-treated patients had fewer complications (68%) than patients treated with medication (80%), even though the diet group had less intensive care for risk factors such as hypertension and hypercholesterolemia. The odds risk ratio for eye disorders and amputations was significantly smaller in the diet-alone group (P<.001 for both). The only parameter that showed similar risks, rather than smaller risk for diet-alone, was that of renal disease. The finding of fewer complications in the diet group held true despite adjustments for age, sex, deprivation, or general practice type.

An example of the lower standards of care in the diet group was that they were 71% less likely to have an A1C recorded, 61% less likely to have cholesterol recorded, 51% less likely to have a microalbinuria testing record, and they had received less advice on risk factors such as smoking and fewer referrals to dieticians or foot care specialists. The diet group was also less likely to have had eye or foot pulse tests.

The diet-treated group, which the authors estimated to include a half-million patients in the UK (1% of the population), was actually more accurately defined as "patients with diabetes not treated with medication" since the amount of dietary intervention was variable and, in some cases, was hard to characterize as treatment. Even though the diet group had fewer complications, the rates were still high—60% for vascular complications, 20% for diabetes-related eye disorders, 9% for neuropathy and 9% for renal complications. The authors suggest that there is room for improvement in the care of diet-alone treated patients and for greater consistency across practices, including surveillance of patients, referrals to dieticians, control of glycemia, blood pressure, and cholesterol, and consensus on when to start medication.