To the Editor We congratulate Donzé and colleagues on their large, multicenter, international study1 validating the HOSPITAL score for predicting readmissions, an important topic. However, there are some potential limitations worth considering that may reduce the usefulness of HOSPITAL in real-world practice.
First, the authors report the predictive accuracy of the HOSPITAL score for predicting potentially avoidable 30-day readmissions, which is inconsistent with the definition of readmissions in the United States subject to financial penalties under the Hospital Readmissions Reduction Program. Further, the SQLape tool used to identify avoidable readmissions is proprietary and has only been validated in Switzerland.2 Preventable readmissions in the United States are highly related to health systems–level factors3 that are likely to be different in the United States vs other countries. Given the uncertainty of whether these readmissions were truly preventable, it would be interesting to know the C-statistic and calibration of the HOSPITAL score for predicting all unplanned readmissions—the primary policy metric in the United States. In a diverse cohort of 16 430 medicine patients from 6 US hospitals, we found the HOSPITAL score had a modest C-statistic of 0.64 for predicting all unplanned 30-day readmissions and did not perform as well as other models, including the LACE index.4
Nguyen OK, Halm EA, Makam AN. Further Limitations of the HOSPITAL Score in US Hospitals. JAMA Intern Med. 2016;176(8):1232-1233. doi:10.1001/jamainternmed.2016.3816