Many patients with obesity hypoventilation syndrome are misdiagnosed as having other respiratory conditions and receive inappropriate therapy, likely contributing to a high mortality rate, according to recent findings.
“The high overall mortality of patients with [obesity hypoventilation syndrome] in our study is alarming,” wrote Paul E. Marik, MD, FCCP, FCCM, professor of medicine and chief of the division of pulmonary and critical care medicine at Eastern Virginia Medical School, and Catherine Chen, MD, resident at Eastern Virginia Medical School. “The 3-year mortality for [obesity hypoventilation syndrome] in our cohort is worse than the current 5-year survival in the USA for breast cancer, colon cancer and prostate cancer and similar to that for all cancers combined. ... A number of factors likely contributed to the high mortality of patients ... however, the misdiagnosis of [obesity hypoventilation syndrome] with inappropriate therapy likely played a major role.”
Paul E. Marik
In a retrospective study, Marik and Chen analyzed electronic records data from 600 patients with “unequivocal” obesity hypoventilation syndrome admitted to Sentara Norfolk General Hospital in Virginia, a tertiary-care teaching hospital, between 2009 and 2013. Included patients had a BMI of at least 40 kg/m², elevated arterial carbon dioxide tension (PaCO), were nonsmokers or smoked fewer than 20 packs per year, and had no evidence of intrinsic pulmonary disease (64% women; 45% white; mean age, 58 years; mean BMI, 48.2 kg/m²; 37% with history of diabetes). Researchers linked the database to available death certificate data.
Researchers found that 43% of patients were misdiagnosed as having chronic obstructive pulmonary disease (mean presenting PaCO, 55.6 mm Hg; mean serum creatinine, 1.59 mg/dL), whereas none had been previously diagnosed with obesity hypoventilation syndrome. The most common admission diagnoses were respiratory failure, heart failure and sepsis; 90 (15%) patients died during the index hospitalization.
The patients’ age, serum creatinine, respiratory failure, sepsis and admission to the
ICU were independent predictors of hospital and posthospital mortality. After a mean 3.2 years of follow-up, 98 of the 510 (19%) hospital survivors died, with an overall cumulative mortality of 31.3%.
“Serum bicarbonate greater than 27 mmol/L is a sensitive and inexpensive marker of established [obesity hypoventilation syndrome] as well as ‘early’ [obesity hypoventilation syndrome],” the researchers wrote. “All patients with a BMI > 35 kg/m² should be screened for [obesity hypoventilation syndrome] using this simple test. Patients with [obesity hypoventilation syndrome] should be referred to a pulmonary and/or sleep specialist for evaluation for [noninvasive positive pressure ventilation], to a dietitian for dietary counseling and lifestyle modification and to a bariatric surgeon for evaluation.” – by Regina Schaffer
The researchers report no relevant financial disclosures.