Severe hypertension linked to pneumonia in elderly
MedWire News: Severe hypertension is an independent predictive factor for stroke-associated pneumonia (SAP) in elderly patients with acute ischemic stroke, researchers say.
Pneumonia is one of the most frequent complications in elderly patients with acute ischemic stroke, Shigeto Morimoto (Kanazawa Medical University, Uchinada, Ishikawa, Japan) and colleagues explain. Although severe hypertension is usually observed in the early phase of acute stroke, few studies have been conducted to assess acute hypertension as a predictor for SAP in elderly stroke patients.
Morimoto et al therefore conducted the present study, which involved 10 elderly patients (mean age 84 years) with acute ischemic stroke and severe hypertension (≥200/120 mmHg), 43 patients with moderate hypertension (160-199/100-119 mmHg), and 65 controlled normotensive or mildly hypertensive (<160/100 mmHg) controls, on admission.
As reported in Hypertension Research, SAP occurred in 38 (30.5%) of the 118 patients. SAP patients had a higher mean systolic blood pressure (BP) than the 80 patients without SAP, at 166 versus 150 mmHg (p=0.006).
Logistic regression analysis adjusted for potential confounders revealed that hypertensive state was independently and significantly associated with a 2.27-fold increased risk for SAP.
Patients with severe hypertension had a 2.83-fold increased risk for SAP compared with patients whose BP was controlled.
After adding previous antihypertensive use as a confounder, hypertensive state was still independently and significantly associated with a 2.26-fold increased risk for SAP on logistic regression analysis, while severe hypertension was significantly associated with a 2.85-fold increased SAP risk, compared with patients who had controlled BP.
Furthermore, conditional logistic regression analysis adjusted for age, gender, Glasgow Coma Scale score, white blood cell count, log serum C-reactive protein, dysphagia, and hypertensive state revealed that patients with severe hypertension on admission had a 5.29-fold increased risk for SAP mortality compared with patients with controlled BP.
The authors speculate that several mechanisms exist for the association between severe hypertension and SAP, including dysphagia, antihypertensive drug therapy, and overactivation of the sympathetic nervous system.
Because SAP is an important cause of death and worse long-term clinical outcome, the association of severe hypertension with poor outcome could, at least in part, be explained by higher SAP death rates and poor functional outcome in those with severe hypertension, say Morimoto and team.
However, due to the small sample size of the study, care must be taken when interpreting the results, they say.
The authors conclude that their findings must be further evaluated in larger trials.
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By Piriya Mahendra