CDC Finds Kidney Injury in One in Three Overdose Hospital Stays

Acute kidney injury was documented in 34.5 percent of the 1,297,847 U.S. hospitalizations tied to drug overdose between 2016 and 2025, and nearly two thirds of those kidney cases involved dialysis, respiratory failure, shock or death in the hospital, CDC researchers reported Thursday.

The analysis, published in Morbidity and Mortality Weekly Report, puts a number on a complication that overdose surveillance has largely skipped over. National tracking has concentrated on fatal overdoses and on nonfatal emergency department visits; what happens to patients after they are admitted, and what it costs them years later, has been a blind spot.

What the researchers counted

The authors — Sola Han, Fang Xu, Hui Xie, Gery Guy and Meda Pavkov, drawn from CDC's Division of Diabetes Translation and Division of Overdose Prevention — analyzed 2016–2025 discharge records in the Premier Healthcare Database, an all-payer system covering roughly 1,400 hospitals and health systems, or about a quarter of annual U.S. inpatient admissions.

They pulled hospitalizations with an ICD-10-CM code for opioid, cocaine or psychostimulant poisoning recorded as present on admission, then flagged those with a kidney injury code in any diagnosis field. Admissions for people with end-stage kidney disease or chronic dialysis dependence were excluded. A hospitalization counted as severe if the patient received acute dialysis or developed respiratory compromise, shock or hypotension, or died before discharge.

One structural caveat runs through every figure: the unit of analysis is a hospitalization, not a person. Someone admitted three times contributes three times.

Older patients develop it more often; younger patients fare worse

Kidney injury rose steadily with age, from 28.2 percent of overdose hospitalizations among patients 24 and younger to 37.4 percent among those 65 and older. Men were more likely to develop it than women, 38.1 percent against 29.4 percent.

The severity gradient ran the other way. Among patients who developed kidney injury, 68.1 percent of those 24 and younger had a severe inpatient course, compared with 56.1 percent of those 65 and older. Women with kidney injury were slightly more likely than men to have a severe course, 61.9 percent versus 60.4 percent.

The report's authors point to differences in what younger patients are using. In a separate line of research on rhabdomyolysis — the muscle breakdown that can overwhelm the kidneys after heavy stimulant use — illicit drug use has been associated with younger age, more severe kidney injury and the need for dialysis. The CDC team also notes that women who develop kidney injury may warrant closer monitoring for shock and other severe complications, since the evidence on sex-specific patterns of hemodynamic instability in overdose-related kidney injury remains thin.

The curve turned in 2022

The share of overdose hospitalizations involving kidney injury climbed between 2016 and 2022, at an annual percentage change of 2.69 percent, then fell between 2022 and 2025, at minus 5.11 percent a year. Severe courses followed a similar arc with a longer lag: up 1.82 percent a year through 2023, then down 2.89 percent a year through 2025.

Those declines have not been uniform. The drop in severe courses was not statistically significant among patients 24 and younger, among those 25 to 44, or among women — the same groups that carry the highest severity burden.

The trends mirror the broader direction of overdose mortality, which has fallen for three consecutive years. But the authors are careful not to claim the two are the same phenomenon, and their data cannot show why either curve moved.

Why a kidney complication matters in overdose care

Acute kidney injury is common in hospital medicine generally — it develops in roughly 20 percent of hospitalized adults — and it is not a transient inconvenience. It raises the risk of chronic kidney disease, kidney failure and death, and it is expensive: an estimated $1,795 in additional cost per hospitalization compared with admissions without kidney injury, rising to $11,016 more when dialysis is required.

Federal guidance calls for kidney function to be checked within three months after an acute injury. Nationally, follow-up is sparse. Among Medicare beneficiaries in 2023, 13.6 percent received that assessment, short of the Healthy People 2030 target of 16.4 percent.

The MMWR authors frame overdose-related kidney injury as one of the more tractable complications in the overdose picture, precisely because the triggering exposure is identifiable. Their recommendations are familiar ones: widen naloxone distribution, expand access to substance use treatment, encourage prompt medical evaluation after a suspected overdose, and build a handoff from the discharge summary to kidney follow-up care. The report argues that younger patients deserve particular attention, not because their kidneys fail more often, but because they have more years left in which incomplete recovery can progress.

For clinicians treating substance use disorder, the practical implication is a lower threshold for checking renal function and a discharge plan that names who will recheck it.

What the numbers cannot say

The authors list the usual limits of administrative data. Hospitals in the database may differ from those outside it in size and location, which constrains generalization. Kidney injury was identified through diagnosis codes rather than laboratory criteria, a method that likely undercounts it. The analysis did not capture intensive care admission or length of stay, so it cannot say whether either drove the severe outcomes, and it did not measure dose, route, timing, adulterants or drug combinations.

One limitation is specific to the era being studied: naloxone became far more widely available after 2019, which may have changed which opioid overdoses resulted in a hospital admission at all. A falling share of kidney injury in the last three years of the window is consistent with several explanations, and the data pick none of them.