UnitedHealth Group has dropped thousands of doctors from its networks in recent weeks, leaving many elderly patients unsure whether they need to switch plans to continue seeing their doctors, the Wall Street Journal reported Saturday. 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. …