Factors associated with undiagnosed obstructive sleep apnoea in hypertensive primary care patients

Objective

In hypertensive primary care patients below 65 years of age, (i) to describe the occurrence of undiagnosed obstructive sleep apnoea (OSA), and (ii) to identify the determinants of moderate/severe OSA.

Design

Cross-sectional.

Setting

Four primary care health centres in Sweden.

Patients

411 consecutive patients (52% women), mean age 57.9 years (SD 5.9 years), with diagnosed and treated hypertension (BP >140/90).

Main outcome measures

Occurrence of OSA as measured by the apnoea hypopnoea index (AHI).

Results

Mild (AHI 5–14.9/h) and moderate/severe (AHI > 15/h) OSA were seen among 29% and 30% of the patients, respectively. Comparing those without OSA with those with mild or moderate/severe OSA, no differences were found in blood pressure, pharmacological treatment (anti-hypertensive, anti-depressive, and hypnotics), sleep, insomnia symptoms, daytime sleepiness, or depressive symptoms. Obesity (BMI > 30 kg/m2) was seen in 30% and 68% of the patients with mild and moderate/severe OSA, respectively. Male gender, BMI > 30 kg/m2, snoring, witnessed apnoeas, and sleep duration >8 hours were determinants of obstructive sleep apnoea.

Conclusion

Previously undiagnosed OSA is common among patients with hypertension in primary care. Obesity, snoring, witnessed apnoeas, long sleep duration, and male gender were the best predictors of OSA, even in the absence of daytime sleepiness and depressive symptoms.Key Words: Depression, hypertension, obstructive sleep apnoea, sleep, sleep disordered breathing, snoringCurrent awareness:

• Obstructive sleep apnoea has been linked to hypertension in sleep clinic populations, but there is a lack of knowledge regarding the occurrence in Swedish hypertensive primary care patients.

Main statements:

• Undiagnosed mild and moderate/severe obstructive sleep apnoea was seen among 29% and 30% of patients, respectively.
• Comparing subjects with mild or moderate/severe obstructive sleep apnoea with those without, no differences were found in blood pressure, self-rated sleep duration, insomnia, daytime sleepiness, or depressive symptoms.
• Male gender, BMI > 30 kg/m00B2, snoring, witnessed apnoeas, and sleep duration >8 hours were determinants of moderate/severe obstructive sleep apnoea in hypertensive primary care patients.