[Incidence of type 2 diabetes and its diagnosis process in the decade 1991-2000 in a primary health care centre].

BACKGROUND AND OBJECTIVE

To determine the annual incidence and reasons for diagnosing type 2 diabetes mellitus (T2DM) from 1991 to 2000.

PATIENTS AND METHOD

We performed a retrospective, longitudinal study. The clinical records of all new cases of T2DM registered in an urban primary care center over a 10-year period were reviewed. The annual incidence and prevalence in the population aged more than 14 years old were calculated. Statistical analyses of temporal trends and periodicity (monthly, seasonal and annual) were performed with ARIMA models (Box-Jenkins), Poisson parametrical regression and semiparametrical (GAM) models.

RESULTS

There were 598 true new cases of T2DM (mean age [SD]: 59.7 [11.4] years; 51.3% women). The most frequent associated cardiovascular risk factors were obesity (58.5%) and hypertension (68.2%). The main reasons for diagnosing T2DM were the presence of previous hyperglycemia (64.7%) and the application of protocols for other cardiovascular risk factors (12.4%).The annual incidence was 37.9 per 10,000 persons (95% CI, 34.9-40.9) with no differences between sexes. The prevalence of T2DM at the beginning and end of the study period was 4.4 (95% CI, 2.0-4.8) and 5.5% (95% CI, 5.2-5.9) (25% relative increase). There was no significant temporal trend in the incidence of T2DM over the years.

CONCLUSIONS

The observed incidence of T2DM is high compared with that reported in other studies. The increase in prevalence was not related to a progressive increase in the incidence. The most frequent reasons for diagnosing T2DM were previous hyperglycemia and the application of protocols for other cardiovascular risk factors. This finding seems to be related to an early diagnosis and could benefit these patients.