Risk Factors for Misdiagnosis of Subarachnoid and Intracerebral Hemorrhage
Objectives. To identify risk factors for misdiagnosis of brain hemorrhage in younger patients. Methods. We performed a nested case-control study among 702 subjects from the Hemorrhagic Stroke Project (HSP). The HSP enrolled men and women ages 18–49 years hospitalized during 1994–1999 for a subarachnoid (SAH) or intracerebral (ICH) hemorrhage in 4 U.S. regions. Case subjects were HSP patients who did not receive an appropriate diagnostic evaluation within 24 hours of consulting a physician. Appropriate evaluation was recognized when a brain CT scan and (if CT negative) LP were completed within 24 hours. For each case, two correctly-diagnosed control subjects were matched on recruitment site and period. We calculated odds ratios (ORs) for the association between risk factors and misdiagnosis. Results. The case group comprised all 54 HSP subjects (7.7%)with a misdiagnosis, including 24 (45%) with ICH and 30 (55%) with SAH. The control group comprised 108 subjects, all successfully matched. Six features were significantly associated with risk for misdiagnosis (95% CI excludes 1): initial evaluation in a physician’s office or by telephone (vs. hospital), OR=18.31 [95% CI=6.86, 48.84], absence of alarm symptoms (photophobia, LOC, focal weakness), OR=5.29 [2.61, 10.74], presence of headache, OR= 5.11 [1.14, 22.95], no history of hypertension, OR=2.05 [1.02, 4.11], college education, OR=1.99 [1.02, 3.89], age < 40, OR=1.99 [1.01, 3.92]. Three other features approached significance: no effortful activity at onset, OR=2.96 [0.82, 10.66], Hispanic ethnicity, OR=2.17 [0.77, 6.15], and absent neck pain, OR=1.65 [0.84, 3.24]. In logistic regression analysis including all 6 significant features, location of initial evaluation and absence of alarm symptoms remained associated with risk for misdiagnosis (p<.05). Conclusion. Physicians are most likely to misdiagnose brain hemorrhage in patients without alarm symptoms who are seen outside a hospital emergency room. Low stroke risk (no hypertension, young age) may be additional risk factors. Efforts to reduce misdiagnosis should be directed at primary care physicians who see low-risk patients with milder symptoms.