[Diversity in studies of the prevalence of systemic arterial hypertension]

To evaluate the information about prevalence of hypertension at a national level, several articles published either within or outside Mexico from 1933 to 1995 were reviewed. Variables about criteria and methodology were considered: the BP readings, method used, cutting points to define hypertension, year for screen. There were 30 papers out of 7 states, 16 reporting the Federal District of Mexico, 3 from Jalisco, 3 from Yucatán and 2 from Tamaulipas, there was only one referring to the State of Mexico, one to Veracruz, one to Michoacán and another referring to Mexicans in USA; as whole population there were two, one by the Instituto Mexicano del Seguro Social and another by Secretaría de Salud. A wide variation in prevalence was found (0.47 to 30.9%) mainly attributed to different sampling, measurements and reporting methodology. Few information was disclosed regarding female and elderly populations. The trend is slightly increasing, as expected accordingly to other information sources, but the problem might actually be masked by bias interference. Most of the studies performed have contributed so far to explore the gross prevalence, but may not reach scientific evidence to base evaluations of preventive interventions. The problem may not just be happening in this country. Variability may be partially controlled following the international recommendations to record arterial blood pressure, but still, there is a lack of recommendations to uniform epidemiological reports. Otherwise the values of hypertension prevalence may not be useful for hypertension surveillance.