The accusations reach all the way to the former chief executive’s office, whom many of the whistle-blowers point to as driving the strategy.

For H.M.A., the timing could not be worse. Shareholders recently approved the planned $7.6 billion acquisition of the company by Community Health Systems, which will create the nation’s second-largest for-profit hospital chain by revenue, with more than 200 facilities. The deal is expected to be completed by the end of the month.

While the lawsuits against H.M.A. provide a stark look at the pressure being put on doctors and hospital executives to emphasize profits over their patients, similar accusations are being raised at other hospital and medical groups as health care in the United States undergoes sweeping changes.

Federal regulators have multiple investigations into questionable hospital admissions, procedures and billings at many hospital systems, including the country’s largest, HCA. Community Health Systems, the Franklin, Tenn., company from which H.M.A. hired its former chief executive in 2008, faces similar accusations that it inappropriately increased admissions. Community is in discussions with federal regulators over a settlement regarding some of the accusations.

The practice of medicine is moving more rapidly than ever from decision-making by individual doctors toward control by corporate interests. The transformation is being fueled by the emergence of large hospital systems that include groups of physicians employed by hospitals and others, and new technologies that closely monitor care. While the new medicine offers significant benefits, like better coordination of a patient’s treatment and measurements of quality, critics say the same technology, size and power can be used against physicians who do not meet the measures established by companies trying to maximize profits.