The Wall Street Journal reports that private insurance provider United Health is dropping thousands of doctors from its Medicare Advantage networks. Medicare Advantage is very popular with senior citizens, but United Health says that “government cuts” will “leave many elderly patients unsure whether they need to switch plans to continue seeing their doctors.”

The insurer said in October that underfunding of Medicare Advantage plans for the elderly could not be fully offset by the company’s other healthcare business. The company also reported spending more healthcare premiums on medical claims in the third quarter, due mainly to government cuts to payments for Medicare Advantage services.

The Journal report said that doctors in at least 10 states were notified of being laid off the plans, some citing “significant changes and pressures in the healthcare environment.” According to the notices, the terminations can be appealed within 30 days.