Acute stroke incidence estimated using a standard algorithm based on electronic health data in various areas of Italy

Aim: to define an algorithm and implement it in various areas of Italy, in order to evaluate acute stroke incidence through current databases. Setting. Lazio, Tuscana, Venezia Aulss 12, Torino Asl 5. Participants: resident-based population in the above mentioned 4 areas during 2002-2004. Main outcome. Annual and triennal incidence rate (Crude 434*, 436* with no hospitalization for stroke diagnosis in the previous 60 months. Moreover, patients with 438* codes in secondary diagnoses and patients with hospital discharge from rehabilitation or long-hospital units were excluded. Results: men have a higher crude incidence rate than women (+30%). The age-specific rates show a large variability among the areas for elderly people (65+ for men and 75+ for women), with higher rates in Toscana in both genders (cases per 100, 000 inhabitants: 260.1 men; 193.1 women). Intermediate values were found in Torino and in Lazio; the lowest values are reported in Venezia (men: 182.5; women: 1368). Standardized mortality rates also present higher mortality levels in the two regional areas (Lazio and Toscana) and lower levels in the two urban areas (Torino and Venezia). Conclusions: It is not easy to evaluate the algorithm. Results seem compatible enough with other studies and show a certain consistency with current mortality data. Different socio-economical characteristics could account for differences in the estimated incidence among areas. However, differences in the quality indicators suggest that a validation study with standardized diagnostic criteria will make quality evaluation of the algorithm possible.