Objective: The objective of this study was to assess the utility of determining serum cardiac troponin I (TcI) levels in the elderly.
Methods: During the nine-month study period, all patients older than 70 years admitted to the emergency department presenting rhabdomyolysis (defined by creatine kinase>500 IU/L) were included in this prospective descriptive study, except for those with acute coronary syndrome or pulmonary embolism. Patients were classified into two groups according to their serum TcI level:>0.15 or<or=0. 15 ng/mL. The groups were compared for clinical, laboratory and treatment variables at inclusion and for mortality at six months.
Results: The study included 67 patients: 30 in the group with TcI>0.15 ng/mL group and 37 in the other group. Clinical and laboratory indicators were similar in the two groups. In contrast, significantly more patients in the TcI>0.15 ng/mL group had been treated with a curative dose of heparin (14 versus 2, p=0.01). This difference between the two groups was noted in both the emergency department and other hospital units. Serum TcI levels were not correlated with creatine kinase levels. Concordance between emergency department diagnosis and discharge diagnosis was 95%. No patient was discharged with a diagnosis of acute coronary syndrome; one patient, with a serum TcI level<or=0.15 ng/mL, was diagnosed with a pulmonary embolism. Fewer than half the patients underwent cardiac ultrasonography. Segmental hypokinesia was observed in only a few cases (6% in the TcI>0. 15 ng/mL group versus 8% in the other group). Mortality at six months was higher among patients with an elevated serum TcI level, but the difference was not significant (23% versus 8%, p=0.07).
Conclusion: This study indicated a trend toward higher mortality among patients with elevated serum TcI levels, although the factors underlying these increased concentrations remain unclear.