Background: The Ministry of Health and Medical Education (MOHME) and the Legal Medicine Organization
(LMO) are the 2 death registration systems in Iran for registering drug-related deaths. The aim of the present
study was to assess the number of undercount and the overlap between the deaths registered by the 2 sources.
Methods: In this descriptive study, according to the 10th revision of the International Classification of
Diseases (ICD-10), the registered data on drug-related deaths in the years 2014-2016, as recorded by the
MOHME and the LMO, were collected and the number of deaths was estimated using 2-source capturerecapture method and Excel and SPSS software.
Findings: The total number of drug-related deaths, as registered by the 2 sources, was 8639 during the
3 years. A major part of the drug-related deaths (75% of the data) had been registered by the LMO and only
25% of deaths had been registered by the MOHME. There was also a small overlap (7.7% of deaths) between
the data from the 2 sources. The final estimation from the capture-recapture model and analysis of sensitivity
showed that, during the 3 years, the total number of drug-related deaths was 14517 [95% confidence interval
(CI):14498-14558]. Based on the complete overlap assumption and 50% of unidentified individuals in the
2 sources, the number of deaths was estimated at 11341 and 12418, respectively. The largest number of
drug-related deaths had occurred within the age range of 25-39 years and in men. Kermanshah, Hamedan,
and Zanjan Provinces (Iran) had the largest number of cumulative incidences of drug-related deaths. Based
on the data provided by the MOHME, the most common cause of death was Methadone poisoning.
Conclusion: There was a small overlap between the MOHME and the LMO in the registration of drug-related
deaths. Failure to enter accurate and correct information has led to miscalculations of these deaths in Iran