PARIS – High relative even after researchers adjusted for all major cardiovascular and COPD prognostic indicators, according to a late-breaker presentation at the annual congress of the European Respiratory Society.
Dr. Benjamin Waschki
Troponin I is detectable in the plasma of most patients with COPD, but relative increases in troponin I correlate with greater relative increases in most cardiovascular and COPD risk factors, according to Benjamin Waschki, MD, Pulmonary Research Institute, LungenClinic, Grosshansdorf, Germany.
The relationship between increased troponin I and increased all-cause mortality was observed in an on-going prospective multicenter cohort of COPD patients followed at 31 centers in Germany. The cohort is called COSYCONET and it began in 2010. The current analysis evaluated 2,020 COPD patients without regard to stage of disease.
There were 136 deaths over the course of follow-up. Without adjustment, the hazard ratio (HR) for death was more than twofold higher in the highest quartile of troponin I (equal to or greater than 6.6 ng/mL), when compared with the lowest (under 2.5 ng/mL) (HR, 2.42; P less than .001). Graphically, the mortality curves for each of the quartiles began to separate at about 12 months, widening in a stepwise manner for greater likelihood of death from the lowest to highest quartiles.
The risk of death from any cause remained elevated for the highest relative to lowest troponin I quartiles after adjusting for cardiovascular risk factors and after adjusting for COPD severity. Again, there was a distinct stepwise separation of the mortality curves for each higher troponin quartile,
Of particular importance, troponin I remained predictive beyond the BODE index, which is a currently employed prognostic mortality predictor in COPD, according to Dr. Waschki. When defining elevated troponin as greater than 6 ng/ML and a high BODE score as greater than 4, mortality was higher for those with a high BODE and low troponin than a high troponin and low BODE, (P less than .001), but a high troponin I was associated with a higher risk of mortality when BODE was low (P less than .001). Moreover, when both troponin I and BODE were elevated, all-cause mortality was more than doubled, relative to those without either risk factor (HR, 2.56; P = .003), Dr. Waschki reported.
After researchers adjusted for major cardiovascular risk factors, such as history of MI and renal impairment, and for major COPD risk factors, such as 6-minute walk test and BODE index, those in the highest quartile had a more than 50% greater risk of death relative to those in the lower quartile over the 3 years of follow-up (HR, 1.69; P = .007), according to Dr. Waschki.
Although troponin I is best known for its diagnostic role in MI, it is now being evaluated as a risk stratifier for many chronic diseases, such as heart failure and chronic kidney disease, explained Dr. Waschki in providing background for this study. He reported that many groups are looking at this as a marker of risk in a variety of chronic diseases.