Do all people with untreated sleep apnea develop hypertension?

This would be hard to determine since sleep apnea often goes undiagnosed. We do know that many can reduce their medication if sleep apnea is diagnosed and treated. The cost of screening large populations for SA to come up with a figure would make the research difficult to finance. As a rule, we avoid saying always or never in medicine.

Obstructive sleep apnea has a number of other harmful effects, e.g. pulmonary hypertension, traffic accidents due to day time sleepiness. If the sleep apnea is due to obesity, then the person is also at risk of obesity related disorders. It would be prudent to consult a pulmonary specialist.

Sleep apnea may aggravate systemic hypertension or a risk factor for resistant hypertension rather than the cause of systemic hypertension. However, sleep apnea may have causal relationship with pulmonary hypertension and effective treatment will lower pulmonary pressure.