More New Jersey hospitals are affiliated with large health systems, increasing prices and medical debt for residents, researchers say; large hospital systems are turning a profit.

Urban Institutea think tank that conducts economic and social policy research, analyzed 10 years of data to explore the link between the number of large companies that control hospitals in a given market and people’s ability to pay their medical bills on time.

The researchers found that patients in counties that experienced larger increases in hospital market concentration between 2012 and 2022 — where a small number of companies increasingly control a large share of the market — had a harder time paying off medical debt. Health experts say the research shows how uncontrolled hospital consolidation harms consumers.