02/08/2026
I found this recent paper to be a little worrisome - the investigators were attempting to understand why 2 similar studies (one Swedish, one American) reported large differences in the proportion of people with atypical femur fractures (AFF) who had a history of taking bisphosphonates (BPs). BPs are a common osteoporosis medication shown to improve bone mass in many people. Unfortunately (and somewhat ironically), for a small proportion of people, BPs actually cause AFFs - atypical, because they are not typical osteoporotic hip fractures.
The investigators didn't discover the reason for the discrepancy between the studies but more concerning to me is the fact that their manual review of the medical and pharmacy records of the American AFF group revealed BP exposure was *much higher* than originally reported.
Swedish cohort: 172 patients, 38 had no recorded BP use (22.1%)
US cohort: 306 patients, 29 originally classified BP-naïve (9.5%), reclassified to 9 BP-naïve (2.9%).
This misclassification of BP exposure means there may be a much stronger link between BPs and AFF than previously reported, at least in California. (The differences between populations remains a mystery.)
The investigators concluded that 'Misclassification of BP exposure occurs and can substantially affect reported rates of BP-naïve AFF...'.
Hmmm, ya think? Science is only as good as its data, guys. It behoves us to collect and report it accurately. Adverse events are just as important as effeciacy findings to the people actually taking the drugs.
Summary We examined if inaccuracies in reported BP treatment in two large cohorts could explain the wide discrepancy observed between different patient cohorts with atypical femur fractures. Assessing BP treatment through manual review of medical and pharmacy records increased the discrepancy, indic...