The article by Khan and colleagues1 highlights the strength of the General Practice Research Database (GPRD) as a research-quality database providing accurate diagnostic data to researchers on a wide range of conditions, and for millions of patients. While the search strategy for this study was broad and inclusive of prescription data, procedures, and smoking in addition to diagnoses, the authors did not identify as many articles as expected.
We published a similar systematic review of the validity of diagnoses in the GPRD2 and found …