A population-based study of transient ischemic attack incidence in Novosibirsk, Russia, 1987-1988 and 1996-1997

Background and Purpose-Population-based data on transient ischemic attack ( TIA) incidence are scarce. This study defines incidence rates of first-ever TIA in Novosibirsk, Russia, during 1987-1997 and compares the incidence of first TIA with that of first stroke. Methods-This is a prospective registry population-based study of all new ca ses of TIA and stroke in an overall population of 455 765 residents of Novo sibirsk. All new TIA and stroke incident cases (whether inpatient or outpat ient) that occurred during 1987-1988 and 1996-1997 study periods were recor ded and analyzed. A 95% CI was estimated for all age- and sex-specific stra ta. Results-During the 2 study periods, a total of 211 patients with first TIA were registered in the population studied. The crude annual TIA incidence r ate per 100 000 residents was 16 (95% CI, 8 to 33) in 1987-1988 and 29 (95% CI, 9 to 87) in 1996-1997; these rates standardized to the European popula tion were 17 (95% CI, 8 to 34) and 27 (95% CI, 9 to 79), respectively. Eigh ty-three percent of TIAs occurred in the carotid arteries (rate, 48/100 000 ), 10% occurred in the vertebrobasilar territory (rate, 6/100 000), and 7% of cases had a TIA of uncertain distribution (rate, 2/100 000). Conclusions-Unlike stroke incidence rate, the incidence rate of TIA in Novo sibirsk is similar to that in other populations and constitutes approximate ly 10% of stroke incidence. For the last decade (1987-1997), there was a te ndency, although statistically insignificant, toward increasing incidence r ate of TIA in the population studied.