Many advocates are also concerned about problems worsening, as Donald Trump returns to the White House.
The president-elect has pledged to protect Medicare, which is government health insurance for over-65s and some younger people. He is known for longstanding criticism of parts of the health industry, such as high prices for medicines.
But he has also vowed to loosen regulation, pursue privatisation and add work requirements to publicly available insurance and cut government spending, of which healthcare is a major part.
“The way things stand today, healthcare is a target,” said David Lipschutz, co-director of the Center for Medicare Advocacy, a non-profit that seeks to advance comprehensive Medicare coverage.
“They’re going to try to take people’s health insurance away or diminish people’s access to it and that’s going in the opposite direction of some of these frustrations and would only make problems worse.”
Republicans, who control Congress, have historically backed reforms aimed at making the health system more transparent, cutting regulation and reducing the government’s role.
“If you take government bureaucrats out of the healthcare equation and you have doctor-patient relationships, it’s better for everybody,” House Speaker Mike Johnson said in a video obtained by NBC News, external last month. “More efficient, more effective,” he said. “That’s the free market. Trump’s going to be for the free market.”
Unhappiness with the health system is longstanding in the US, where experts – including at KFF – point out that care is more expensive than in other countries and performance is worse on basic metrics such as life expectancy, infant mortality and safety during childbirth.
The US spent more than $12,000 (£9,600) per person on healthcare in 2022 – almost twice the average of other wealthy countries, according to the Peter G Peterson Foundation, external.
The last major reform, under former president Barack Obama in 2010, focused on expanding health insurance in hopes of making care more accessible.
The law included measures to widen eligibility for Medicaid, another government programme that helps cover medical costs for people with limited incomes. It also forbid insurers from rejecting patients with “pre-existing conditions”, successfully reducing the share of the population without insurance from about 15% to roughly 8%.
Today, about 40% of the population in the US gets insurance from taxpayer-funded government plans – mostly Medicare and Medicaid – with coverage increasingly contracted out to private companies.
The remainder are enrolled in plans from private companies, which are typically selected by employers and paid for with a mix of personal contributions and employer funds.
Even though more people are covered than ever before, frustrations remain widespread. In a recent Gallup poll, external, just 28% of respondents rated health care coverage excellent or good, the lowest level since 2008.
Public data on the rate of insurance denials – which can also happen after care has been received, leaving patients with hefty bills – is limited.
But surveys of patients and medical professionals suggest insurance companies are requiring more “prior authorisation” for procedures – and rejections by insurance companies are on the rise.
In the state of Maryland, for example, the number of claim denials disclosed by insurers has jumped more than 70% over five years, according to reports from the state attorney general’s office.
“The fact that we pay into the system and then when we need it, we can’t access the care we need makes no sense,” said Ms Ginkel. “As I went through the process, it felt more and more like [the insurance companies] do this on purpose in hopes you’re going to give up.”
Brian Mulhern, the Rhode Islander who put off his colonoscopy, compared the industry to the “legal mafia” – offering protection “but on their terms”. He added: “It increasingly seems to be that you can pay more and more and get nothing.”
AHIP, a lobby group for health insurers, said claims denials often reflected faulty submissions by doctors, or pre-determined decisions about what to cover that had been made by regulators and employers.
UnitedHealthcare did not respond to a BBC request for comment for this article. But in an opinion piece written after the killing of its CEO Brian Thompson, Andrew Witty, head of the firm’s parent company, defended the industry’s decision-making.
He said it was based on a “comprehensive and continually updated body of clinical evidence focused on achieving the best health outcomes and ensuring patient safety”.
But critics complain that a for-profit health system will always be focused on its shareholders and bottom line, and have linked the surge in claims denial to the rising using of allegedly error-prone artificial intelligence (AI) to review requests.
One developer said last year its AI tool was not being used to inform coverage decisions – only to help guide providers on how to aid patients.
