Angina pectoris and intermittent claudication are independent predictors of CHD- and all-cause mortality in Russian men. More than 30-years follow-up
Authors: Shalnova S , Yarovaya E , Kutsenko V , Kapustina A , Makarova Y.U , Imaeva A , Balanova Y 
Published: November 2020

Abstract

Background
Angina pectoris (AP) and intermittent claudication (IC) are transient ischemic conditions provoked by exertion due to an imbalance of oxygen supply and demand to the skeletal leg muscle and/or myocardium. They have the similar etiology, both are accepted markers of diffuse atherosclerotic vascular disease and increased mortality risk. But these conditions were rarely studied in community-based cohorts, including comparison with each other or with individuals without symptoms.

Aim
To investigate the relationship between AP and IC and to evaluate their impact on the survival among Russian men during 30-years follow-up.

Methods
The data was obtained from representative samples observed in Moscow and Leningrad (now Saint-Petersburg) from 1975 to 1986. Men (10953) aged 35–71 years (mean age 48.8±6.61yrs) were examined by the same core protocol. AP and IC were determined by the original Rose questionnaires. We identified five risk groups of participants: 1) AP and IC; 2) AP without IC; 3) IC without AP; 4) without AP and IC, suffering from chest or leg pain that makes them stop (mixed group); and 5) men without pain, that makes them stop (no pain). During the 31-year follow up period (median time to event – 21.9 years) 7893 deaths from all-causes including 2673 from CHD occurred. We used Kaplan-Meier curves to investigate the relationship between risk groups and survival. Individual impact of AP and IC into mortality was evaluated by multivariate age-adjusted Cox proportional hazards model. For this, we divided participants with AP into three groups: with typical AP, with chest pain that makes them stop, but without AP (mixed group) and other (no pain); and with IC into four groups: with typical IC, with atypical IC, with no pain in legs and all other (mixed group).

Results
Only 4.8% men with AP had IC, whereas 28.6% with IC had AP. All-cause mortality Kaplan-Meier curves were pairwise different, except groups with “IC without AP” and “AP without IC”. The same results were obtained for CHD mortality. Difference of 17.2 years for median survival times were observed between “no pain” and “AP and IC” groups (Figure 1). We revealed significant impact of each IC and AP group on all-cause mortality. The same results were obtained for CHD mortality except for mixed IC group. Hazard ratios (95% confidence interval) for typical AP and typical IC groups were 1.99 (1.18–2.27) and 2.47 (1.84–3.30) compared to “no pain” group, respectively. They did not significanly differ from each other.

Limitations
We observed natural history of IC using the original Rose questionnaire in baseline. No modern methods of diagnostics were used that time.

Conclusion
The greatest decrease in life expectancy of 17.2 years was among participants with “AP and IC”. Survival curves of “IC without AP” and “AP without IC” groups didn't differ. IC and AP significantly independent age-adjusted impacts on all-cause and CHD mortality.
Survival curves for all-cause mortality

Funding Acknowledgement
Type of funding source: None