Objective: To assess the potential under-registration of work-related accidents in the Mexican Institute of Social Security.
Material and methods: A countrywide cross-sectional study was carried out with information collected from 27 district offices of the Mexican Institute of Social Security (MISS), on workers seen at MISS emergency rooms during November 2001 because of a probable accident at work. We compared these reports to official records of work-related accidents to estimate the proportion of incomplete reports. Data analysis consisted of descriptive statistics for each variable; the annual estimation of incomplete reporting proportions was made by multiplying by twelve months; 95% confidence intervals were estimated using Poisson's exact method for a proportion.
Results: Data from 27 out of 37 MISS district offices revealed that 7211 cases were not recognized as work accidents, accounting for an underestimation of 26.3%, ranging between 0 and 68% among the different district offices. The accidents that were most frequently left unregistered were mild and blunt injuries.
Conclusions: Under-registration can affect worker compensation plans and the financial balance of the institution's occupational risk insurance. Research is needed to investigate and eliminate the causes of under-registration. Employers, the industry, and health institutions should be involved in this effort. The English version of this paper is available at: http://www.insp.mx/salud/index.html.