Vascular risk profiles for predicting outcome and long-term mortality in patients with idiopathic normal pressure hydrocephalus: comparison of clinical decision support tools

Abstract

OBJECTIVE Vascular risk factors (VRFs) may act synergistically, and clinical decision support tools (CDSTs) have been developed that present vascular risk as a summarized score. Because VRFs are a major issue in patients with idiopathic normal pressure hydrocephalus (INPH), a CDST may be useful in the diagnostic workup. The objective was to compare 4 CDSTs to determine which one most accurately predicts short-term outcome and 10-year mortality after CSF shunt surgery in INPH patients. METHODS One-hundred forty INPH patients who underwent CSF shunt surgery were included. For each patient, 4 CDST scores (Systematic Coronary Risk Evaluation–Older Persons [SCORE-OP], Framingham Risk Score [FRS], Revised Framingham Stroke Risk Profile, and Kiefer’s Comorbidity Index [KCI]) were estimated. Short-term outcome (3 months after CSF shunt surgery) was defined on the basis of improvements in gait, Mini-Mental State Examination score, and modified Rankin Scale score. The 10-year mortality rate after surgery was noted. The CDSTs were compared by using Cox regression analysis, receiver operating characteristic curve analysis, and the chi-square test. RESULTS For 3 CDSTs, increased score was associated with increased risk of 10-year mortality. A 1-point increase in the FRS indicated a 2% higher risk of death within 10 years (HR 1.02, 95% CI 1.003–1.035, p = 0.021); SCORE-OP, 5% (HR 1.05, 95% CI 1.019–1.087, p = 0.002); and KCI, 12% (HR 1.12, 95% CI 1.03–1.219, p = 0.008). FRS predicted short-term outcome of surgery (p = 0.024). When the cutoff value was set to 32.5%, the positive predictive value was 80% and the negative predictive value was 48% (p = 0.012). CONCLUSIONS The authors recommend using FRS to predict short-term outcome and 10-year risk of mortality in INPH patients. The study indicated that extensive treatment of the risk factors of INPH may decrease risk of mortality. Clinical trial registration no.: NCT01850914 (ClinicalTrials.gov)