We all have items left unfinished from 2017. It's hard to accomplish everything. But when it comes to addressing important health-care issues, the list that Congress amassed is striking.

Of the most important health-care challenges crying out for attention, here is my list of the top five left unresolved in 2017 and in desperate need of attention in 2018. All are crucial, so the order is more or less arbitrary.

  1. Funding to fight opioid abuse

Opioid overdoses took the lives of more than 64,000 Americans in 2016. In October, President Trump declared an "emergency," and the chair of his opioid commission, Gov. Christie, urgently called on Congress to appropriate additional funding to fight the epidemic.

Yet, over the summer, Congress considered doing the opposite through drastic cuts to Medicaid, which is a crucial source of support for prevention and treatment. Fortunately, the legislation did not pass. Despite Trump's appointment of White House counselor Kellyanne Conway as opioid "czar" in November, needed funding to fight the plague has yet to be provided.

  1. Taming drug price increases

The relentless march of drug price increases continued unabated in 2017. There were 40 in the first quarter of 2017 alone. The price of one cancer medication, lomustine, more than doubled in 2017 for an increase of 1,400% since 2013. During the presidential campaign, Trump asserted that drug companies were "getting away with murder" and promised action, if elected. Little has been done so far, and Congress has yet to step in.

  1. Funding ACA cost-sharing reductions

Among the Affordable Care Act's provisions to help low-income patients is one that requires insurance companies to waive cost-sharing payments (copayments and deductibles) for many with incomes below 250 percent of the federal poverty level. The federal government is supposed to reimburse them for the cost, but Congress never appropriated the funding. Trump ended an Obama work-around, which has led some insurers to threaten hefty price increases to cover the expected shortfall.

A bipartisan group of senators supports legislation to appropriate the funds, and Sen. Susan Collins (R., Maine) conditioned her vote for tax reform on a promise that a bill would be brought forward. This might happen in January, but it remains a question mark.

  1. Reauthorizing the Children's Health Insurance Program

The CHIP program provides health-care coverage for almost nine million children in low-income families whose incomes fall just above the cut-off for Medicaid. Authorization for federal funding expired in September, and Congress passed only a temporary extension. The program enjoys wide bipartisan support, but legislation for full reauthorization is still pending. Millions of children stand to lose health insurance without it.

  1. Improving (or replacing) the ACA

Congressional Republicans have been promising for more than seven years to "repeal and replace" the ACA. During the spring and summer, they considered proposals that would repeal the law without including much of a replacement and would leave an estimated 22 million additional American uninsured over the next 10 years. The recently passed tax reform law repeals a key element of the ACA, the individual insurance mandate penalty, which will take insurance away from an estimated 13 million Americans.

At the same time, there are numerous proposals to improve the law and actually add millions of Americans to insurance rolls, but none garnered serious congressional attention. Perhaps if Congress focused on increasing coverage rather than taking it away, consensus could be achieved.

That's a sizeable list of unfinished business for matters that directly affect the lives and health of millions of Americans. Congressional Republicans were able to rally their forces to pass an extremely complex and sweeping tax overhaul in 2017. Will they be able to do the same in 2018 for pressing health-care issues? We'll see.

Robert I. Field is a professor at Drexel University Kline School of Law and Drexel's Dornsife School of Public Health.