Elevation of Serum Creatine Phosphokinase in Hospitalized Patients

Background: The clinical characteristics and outcomes of patients with significant noncardiac and cardiac serum creatine phosphokinase (CPK) elevations are not well described. Methods: One hundred fifty-eight inpatients who had CPK elevation of >1000 IU/L were identified. One hundred thirty-seven patients whose CPK elevations could be attributed to either noncardiac or cardiac etiologies were included and analyzed for clinical characteristics, 30-day, 3-month, and 1-year all-cause mortality rates. Twenty-one patients were excluded, in whom noncardiac and cardiac CPK (CCPK) elevations coexisted, or etiologies were unclear. Results: Of the 137 patients, 43 (31%) patients had CCPK elevation and 94 (69%) patients had noncardiac CPK (NCCPK) elevation. One-year mortality rate was 26.6% (25 of 94 patients) in NCCPK elevation group. Decedents were older (P < 0.05), had higher blood urea nitrogen (P < 0.01) and creatinine (P < 0.05) levels, and had higher white blood cell counts (P < 0.05) compared with survivors. In CCPK elevation group, 37.2% (16 of 43 patients) died within 1 year after admission. Decedents were also older (P < 0.01) and had higher blood urea nitrogen (P < 0.01) and creatinine (P < 0.01) levels. Conclusion: The incidence of NCCPK elevation is greater than that of CCPK elevation in a veteran, mostly male, population. One-year mortality rate in patients with NCCPK elevation is comparable to that in patients with CCPK elevation (26.6% versus 37.2%, P = 0.290). Age and renal insufficiency are 2 major predictors for increased mortality in both groups.