An important study was published this week in the Annals of Internal Medicine, “Survival Comparison of Patients With Cystic Fibrosis in Canada and the United States,” by Anne L. Stephenson and colleagues.1 The investigators used cystic fibrosis (CF) registries in the United States and Canada to compare outcomes for these patients between the two countries, and the bottom line made headlines in major media outlets: Canadian CF patients did better—much better—indeed they lived some 10 years longer than US CF patients. The investigators found 34% lower mortality for Canadian CF patients even after controlling for a wide variety of patient and clinical characteristics, including genotype, an important marker of disease severity. This difference was demonstrated in multiple subgroup analyses (for instance, when looking only at delta F508 homozygotes). Moreover, over time, Canadian CF patients saw greater improvements in life expectancy. Finally, they were also more likely to receive organ transplants.
Thus, despite the often-vaunted superiority of the American healthcare system, here is yet another piece of evidence that single payer public systems can deliver better results—indeed in this case the Canadian system even provided more high-technological care (i.e. transplants), which is supposed to be our specialty.
There is one additional finer point to make. When examining US CF patients by insurance status, the investigators found that those with private insurance did not do significantly worse than Canadian CF patients, whereas the uninsured and those with Medicare/Medicaid (treated as one category) did. Does this somehow provide evidence that private insurance is superior to public insurance, or does it weaken the overall point that the Canadian single payer system better served CF patients? No, for a number of reasons. First, Medicaid, as important as it is, does in fact sometimes provide a lower tier of access to medical care: for instance, CF patients with Medicaid are less likely to be accepted for a lung transplantation in the US.2 Thus, even apart from the possibility of residual confounding given the association of Medicaid with lower socioeconomic status, it would not be surprising to find worse outcomes for those with Medicaid as compared to those with private insurance in the US. Second, it is hard to use this study to say much about Medicare. In part, this is because subjects with Medicaid and Medicare were combined into a single group, so it’s unclear which (or both) of these populations were driving the finding. Additionally, those under 65 can only get Medicare if they are disabled. Comparing this disabled CF population to a general Canadian CF population would leave the door open for residual confounding.
- Stephenson AL, Sykes J, Stanojevic S, et al. Survival comparison of patients with cystic fibrosis in canada and the united states: A population-based cohort study. Annals of internal medicine 2017.
- Quon BS, Psoter K, Mayer-Hamblett N, Aitken ML, Li CI, Goss CH. Disparities in Access to Lung Transplantation for Patients with Cystic Fibrosis by Socioeconomic Status. American Journal of Respiratory and Critical Care Medicine 2012;186:1008-13.