Cost analysis of once-daily ISMN versus twice-daily ISMN or transdermal patch for nitrate prophylaxis

Impact of reducing dosing frequency on adherence to oral therapies: a literature review and meta-analysis

OBJECTIVES

To assess the impact of reduced frequency of oral therapies from multiple-dosing schedules to a once-daily (OD) dosing schedule on adherence, compliance, persistence, and associated economic impact.

METHODS

A meta-analysis was performed based on relevant articles identified from a comprehensive literature review using MEDLINE® and Embase®. The review included studies assessing adherence with OD, twice-daily (BID), thrice-daily (TID), and four-times daily (QID) dosing schedules and costs associated with optimal/suboptimal adherence among patients with acute and chronic diseases. Effect estimates across studies were pooled and analyzed using the DerSimonian and Laird random-effect model.

RESULTS

Forty-three studies met inclusion criteria, and meta-analyzable data were available from 13 studies. The overall results indicated that OD schedules were associated with higher adherence rates (odds ratio [OR] 3.07, 95% confidence interval [CI] 1.80-5.23; P < 0.001 for OD versus > OD dosing) and compliance rates (OR 3.50, 95% CI 1.73-7.08; P < 0.001 for OD versus > OD dosing); persistence rates showed the same direction but were not statistically significant (OR 1.43, 95% CI 0.62-3.29; P = 0.405 for OD versus BID dosing). Results for each of the conditions were consistent with those observed overall with respect to showing the benefits of less frequent dosing. From a health economic perspective, higher adherence rates with OD relative to multiple dosing in a number of conditions were consistently associated with corresponding lower costs of health care resources utilization.

CONCLUSION

Current meta-analyses suggested that across acute and chronic disease states, reducing dosage frequency from multiple dosing to OD dosing may improve adherence to therapies among patients. Improving adherence may result in subsequent decreases in health care costs.

Economic implications of nonadherence to highly active antiretroviral treatment in HIV patients

Until now, the economic implications of nonadherence to drug therapies have been mostly assessed in a cost perspective and understood as the impact of nonadherence behaviours on the cost-effectiveness ratios of particular therapies. In HIV disease, some modelling approaches have suggested that high adherence levels might improve the cost-effectiveness of highly active antiretroviral treatment regimens. However, there is an urgent need for research directly observing and measuring the costs of nonadherence behaviours. In addition to this cost perspective, the authors argue that the economic impact of nonadherence should also be studied in a microeconomic--patient-oriented--perspective. Major implications of this microeconomic perspective are drawn. First, the microeconomic approach highlights that nonadherence may often be a rational choice of the patient, thus suggesting new ways for improving adherence. Second, it implies that the adherence behaviour can be interpreted as an indicator of patients' subjective valuation of highly active antiretroviral treatment therapies; in particular, higher levels of adherence are associated with higher patient well-being. Third, it shows that the adherence behaviour cannot be regarded as an exogenous variable when the impact of adherence on health outcome or on cost-effectiveness ratios is studied, thus requiring the use of specific statistical or econometric methods.

The impact of non-compliance on the cost-effectiveness of pharmaceuticals: a review of the literature

Non-compliance with drug therapies not only limits their effectiveness, but in some instances, is associated with grave clinical sequelae and substantial economic burden. It is important, therefore, to consider non-compliance in economic evaluations. A review of pharmacoeconomic evaluations, which have applied sensitivity analysis to non-compliance rates, was undertaken to evaluate the impact of non-compliance on the cost-effectiveness of different drug therapies. Although 22 evaluations satisfied the inclusion criteria, additional information was obtained from the authors of most studies, as the published details were inadequate. The majority of evaluations assumed altered effectiveness owing to reduced compliance in the absence of supportive clinical evidence. Because of the disparity in the nature of the outcomes, the measures of non-compliance and the time horizon of the studies evaluated, it was not possible to compare the magnitude of the impact of non-compliance among different drug-disease combinations. However, it was evident that non-compliance always results in a reduction in efficacy, but its impact on costs varied substantially. The importance of incorporating measures of compliance is highlighted, as failing to account for 'real world' compliance rates in pharmacoeconomic evaluations may lead to selection of sub-optimal treatment strategies.