Potential bias of instrumental variable analyses for observational comparative effectiveness research.

Instrumental variable analysis is an increasingly popular method in comparative effectiveness research (CER). In theory, the instrument controls for unobserved and observed patient characteristics that affect the outcome. However, the results of instrumental variable analyses in observational settings may be biased if the instrument and outcome are related through an unadjusted third variable: an "instrument-outcome confounder." The authors identified published CER studies that used instrumental variable analysis and searched the literature for potential confounders of the most common instrument-outcome pairs. Of the 187 studies identified, 114 used 1 or more of the 4 most common instrument categories: distance to facility, regional variation, facility variation, and physician variation. Of these, 65 used mortality as an outcome. Potential unadjusted instrument-outcome confounders were observed in all studies, including patient race, socioeconomic status, clinical risk factors, health status, and urban or rural residency; facility and procedure volume; and co-occurring treatments. Only 4 (6%) instrumental variable CER studies considered potential instrument-outcome confounders outside the study data. Many effect estimates may be biased by the failure to adjust for instrument-outcome confounding. The authors caution against overreliance on instrumental variable studies for CER.

Improving access to medicines in low and middle income countries: corporate responsibilities in context.

More than two billion people in low- and middle-income countries (LMIC) lack adequate access to essential medicines. In this paper, we make strong public health, human rights and economic arguments for improving access to medicines in LMIC and discuss the different roles and responsibilities of key stakeholders, including national governments, the international community, and non-governmental organizations (NGOs). We then establish a framework of pharmaceutical firms' corporate responsibilities - the "must," the "ought to," and the "can" dimensions - and make recommendations for actionable business strategies for improving access to medicines. We discuss controversial topics, such as pharmaceutical profits and patents, with the goal of building consensus around facts and working towards a solution. We conclude that partnerships and collaboration among multiple stakeholders are urgently needed to improve equitable access to medicines in LMIC.

Impact of universal health insurance coverage in Thailand on sales and market share of medicines for non-communicable diseases: an interrupted time series study.

OBJECTIVE: In 2001, Thailand implemented the Universal Coverage Scheme (UCS), a public insurance system that aimed to achieve universal access to healthcare, including essential medicines, and to influence primary care centres and hospitals to use resources efficiently, via capitated payment for outpatient services and other payment policies for inpatient care. Our objective was to evaluate the impact of the UCS on utilisation of medicines in Thailand for three non-communicable diseases: cancer, cardiovascular disease and diabetes. DESIGN: Interrupted time-series design, with a non-equivalent comparison group. SETTING: Thailand, 1998-2006. DATA: Quarterly purchases of medicines from hospital and retail pharmacies collected by IMS Health between 1998 and 2006. INTERVENTION: UCS implementation, April-October 2001. OUTCOME MEASURES: Total pharmaceutical sales volume and percent market share by licensing status and National Essential Medicine List status. RESULTS: The UCS was associated with long-term increases in sales of medicines for conditions that are typically treated in outpatient primary care settings, such as diabetes, high cholesterol and high blood pressure, but not for medicines for diseases that are typically treated in secondary or tertiary care settings, such as heart failure, arrhythmias and cancer. Although the majority of increases in sales were for essential medicines, there were also postpolicy increases in sales of non-essential medicines. Immediately following the reform, there was a significant shift in hospital sector market share by licensing status for most classes of medicines. Government-produced products often replaced branded generic or generic competitors. CONCLUSIONS: Our results suggest that expanding health insurance coverage with a medicine benefit to the entire Thai population increased access to medicines in primary care. However, our study also suggests that the UCS may have had potentially undesirable effects. Evaluations of the long-term impacts of universal health coverage on medicine utilisation are urgently needed.