Comparative assessment of the dynamics of the incidence of pulmonary and etraulmonary tuberculosis in St. Petersburg for half a century of observation

Abstract

This article describes the results of comparative analysis of the dynamics of incidence of pulmonary tuberculosis (TBP), extrapulmonary extrarespiratory tuberculosis (TBER) and respiratory extrapulmonary tuberculosis (TBREP) in St. Petersburg (Leningrad) from 1970 to 2019. Throughout the 50 years of observation, epidemiological situation for TBP, especially for TBER, hasmuch improved, with incidence of the latter going down 30 times. Five stages (decades) were identified, within which the factors demonstrate practically the same impact, the growth rate of indicators was calculated for each stage (the value of indicators at the beginning of each stage taken as 100%).

The first stage was a simultaneous reduction in the incidence rate in all categories of TB localization against the background of socio-economic factors positive effect and organization of effective and  comprehensive anti-TB measures. In the second stage (1980ies, a period of growing socio-economic problems), the positive dynamics of TB incidence stopped and switched to stabilization at a low level. Indicators became more volatile, while TB dynamics by localization more and more desynchronized.

Тhe third stage (1990iеs, a period of social and economic crisis) was char-acterised by a sharp increase of TB incidence, especially TBREP, with a switch to stabilization at a high level. The fourth stage (2000 through 2009, the beginning of TB control system restoration) demonstrated the indicators’ dynamics desynchronization: the incidence of TBP and TBREP has stabilized, and TBER continued to decline. The fifth stage (2009 through 2019, complete restoration of TB control system) showed a steady trend of incidence rate reduction and return of uniformity in incidence rate of various localizations. There is no increase in the proportion of extrapulmonary TB expected for the incidence decline. TBER incidence had been declining in most stages, with the exception of the 90ies, which could be explained by substandard work in identifying patients, and the rarity of TBER etiological verification. It is necessary to raise the  clinical awareness of narrow specialists and general practitioners in the diagnostic problems associated with TBER.

The coincidence of the rate of TB incidence decrease in main localizations in the 1970ies and 2010s proves that a comprehensive state strategy to combat tuberculosis can provide a high rate of TB incidence decrease in various social layers with positive social and economic conditions of life of the population.