“Our analysis is subject to limitations beyond those already described. First, any limitations in GBD 2016 cause-of-death estimation are also applicable to this study.²⁷ For GBD 2016, we aimed to better account for cause-of-death data quality by developing a metric for well-certified deaths and using this measure to inform GBD data standardisation and correction processes. Nonetheless, establishing and maintaining high-quality vital registration systems is essential to improved cause-of-death estimation. For instance, abrupt or prolonged conflict can lead to cause-of-death data gaps or lags in reporting; subsequently, HAQ Index performance might not yet fully capture the ramifications of conflict on health care in some locations. Second, continued updates to the GBD comparative risk assessment improved risk-standardisation of amenable causes, but we might not account for all possible differences in mortality related to underlying risk exposure. Third, our scaling approach (ie, transforming each cause to a scale of 0–100) does not allow for the potential for additional improvements in reducing cause-specific mortality. How to establish empirically-derived lower bounds for each cause remains unclear, but future work should consider the use of alternative scaling methods. Fourth, the HAQ Index does not expressly capture possible effects of personal health care on causes without substantial mortality. Although performance on these causes might be well correlated with the current HAQ Index formulation, their inclusion could strengthen overall measurement. Fifth, the HAQ Index does not explicitly distinguish between the effects of primary and secondary care,⁶⁶ though some causes might give a stronger signal on certain health-system dimensions (eg, surgical intervention for appendicitis). Improved performance in particular therapeutic areas might represent a combination of advances in primary care (eg, diagnosis and treatment of hypertension) and secondary or referral services (eg, stroke unit, cardiology), or overall gains in continuums of care. Finally, our exploratory analysis of HAQ Index performance did not account for all potential factors related to health-care access and quality; future work should consider how other dimensions of health financing and health care are associated with the HAQ Index (eg, catastrophic health spending, insurance coverage), as well as broader social determinants of health (eg, poverty, accessibility).⁶⁷“

Source: GBD 2016 Healthcare Access and Quality Collaborators. “Measuring performance on the Healthcare Access and Quality Index for 195 countries and territories and selected subnational locations: a systematic analysis from the Global Burden of Disease Study 2016.” Lancet (London, England) vol. 391,10136 (2018): 2236-2271. doi:10.1016/S0140-6736(18)30994-2 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986687/