The association between adherence to oral anti-diabetic drugs and hypoglycaemia in persons with Type 2 diabetes.

AIM: To quantify the relationship between adherence to oral anti-diabetic drugs and incident hypoglycaemia in Type 2 diabetes. METHODS: Utilizing a claims database, we identified patients with Type 2 diabetes initiating metformin, sulphonylureas or thiazolidinediones and classified adherence over the next 6 months, creating markers of changes in therapy (switches/additions). We created nine mutually exclusive exposure groups, including: metformin ≥ 80% adherence; metformin < 80% adherence; sulphonylurea ≥ 80% adherence; sulphonylurea < 80% adherence; thiazolidinediones ≥ 80% adherence; thiazolidinediones < 80% adherence; switching to a new class; adding on therapy; and switching to two or more different classes of medication. We followed patients for incident hypoglycaemia medical visits and developed a Cox proportional hazards model to compare rates of hypoglycaemia across exposure groups. RESULTS: Adherence to monotherapy was high (86.0 ± 17.8% for metformin, 87.2 ± 17.5% for sulphonylureas and 87.8 ± 16.9 for thiazolidinediones). The incidence of hypoglycaemia ranged from 93.1 to 259.9 per 10 000 person-years in the nine exposure groups. Relative to metformin users with ≥ 80% adherence, those switching from any monotherapy to combination therapy had a 32% increased rate (hazard ratio 1.32; 95% CI 1.07-1.64) of hypoglycaemia. Thiazolidinediones users with ≥ 80% adherence had a decreased hazard rate (hazard ratio 0.67; 95% CI 0.46-0.98) relative to metformin users with ≥ 80% adherence. All other groups on oral anti-diabetic drugs, regardless of adherence, were not associated with hypoglycaemia CONCLUSIONS: We found that the relative rate of hypoglycaemia was highest in patients switching from monotherapy to combination therapy, while rates of hypoglycaemia in monotherapy users were largely unrelated to level of adherence.

Oral anti-diabetic drugs for the prevention of Type 2 diabetes.

AIM: To determine the comparative efficacy of oral anti-diabetic drugs in preventing the development of Type 2 diabetes. METHODS: A systematic literature search of MEDLINE, EMBASE and Cochrane CENTRAL was conducted for randomized controlled trials evaluating oral anti-diabetic drugs in patients at high risk for developing Type 2 diabetes. Mixed-treatment comparison meta-analysis methods were used to evaluate the relative risks and risk differences of developing Type 2 diabetes, along with associated 95% credible intervals. RESULTS: Overall, 20 trials (n = 23 230 participants) were included. Upon mixed-treatment comparison meta-analysis, thiazolidinediones, alpha-glucosidase inhibitors and biguanides significantly reduced the relative risk of developing diabetes by 64, 40 and 27%, respectively, compared with control. Sulphonylureas and glinides showed no significant effect. Moreover, thiazolidinediones significantly reduced the relative risk of diabetes by 50% compared with biguanides and trended towards a 40% risk reduction vs. alpha-glucosidase inhibitors [relative risk 0.60 (95% credible intervals 0.34-1.02)]. None of the results were appreciably altered upon subgroup or sensitivity analyses. When evaluating risk differences compared with control, thiazolidinediones (-9%, number needed to treat = 11), alpha-glucosidase inhibitors (-7%, number needed to treat = 14) and biguanides (-7%, number needed to treat = 14) continued to show significant benefit. CONCLUSIONS: Of the oral anti-diabetic drugs evaluated to prevent Type 2 diabetes, thiazolidinediones were associated with the greatest risk reduction compared with control and associated with greater risk reduction than biguanides. Alpha-glucosidase inhibitors and biguanides performed similarly, and better than control, while sulphonylureas and glinides provided no significant benefit.

Cost of medication-related problems at a university hospital.

The cost to an institution of medication-related problems (MRPs) was studied. A retrospective chart review covering the period from July 1992 through June 1994 was performed for patients at a university-affiliated medical center hospital who were known to have had clinical consequences from an adverse drug reaction (ADR) or medication error. All interventions resulting directly from the problem were recorded. A detailed list of patient charges was reviewed for each patient, and specific charges for the MRP-associated interventions were tabulated. The clinical outcomes used to evaluate intervention costs were categorized as extra laboratory tests, noninvasive procedures, additional treatments, invasive monitoring or procedures, increased length of stay, and intensive care. The cost of each intervention was calculated by applying the cost-to-charge ratio used in the institution's patient-charge-based accounting system. A total of 109 patient charts were reviewed. A total of 349 clinical outcomes associated with MRPs, or an average of 3 outcomes per patient, were detected. The mean +/- S.E. cost of MRP-associated clinical outcomes to the institution ranged from $95 +/- 11 for additional laboratory tests to $2640 +/- 596 for intensive care. The next most costly outcomes were increased length of stay and invasive monitoring or procedures. For the 1911 MRPs reported in 1994, the estimated total cost was almost $1.5 million. A review of the medical records of patients for whom an ADR or medication error had been recorded showed a high cost of these events to the institution, with the cost varying with clinical outcome, and a correspondingly strong opportunity for pharmacists to intervene to save money and improve the quality of care.