Across every major inpatient diagnosis category, the amount Medicare beneficiaries pay out of pocket for a hospital stay grew faster over the past decade than what Medicare itself paid. That's not a rounding error or a quirk of one procedure. It's a consistent pattern across the 20 highest-volume DRGs in the program.

The gap between total payment and Medicare's share, a reasonable approximation of beneficiary cost-sharing, rose by at least 42% in every single high-volume DRG from 2013 to 2023. For some of the most common and serious conditions, the increase was far steeper.

Sepsis Patients Are Absorbing the Sharpest Increases

Septicemia without mechanical ventilation (DRG 871) is now the single highest-volume inpatient diagnosis in Medicare, with 561,177 discharges in 2023, up from 403,847 in 2013. The beneficiary cost-sharing gap for that DRG rose from $1,587 to $2,554, a 60.9% increase over the decade. As a share of total payment, beneficiary exposure climbed from 11.4% to 14.5%, a 3 percentage point shift.

The related DRG 872 (septicemia without MCC) tells a similar story: the gap rose 59.1%, from $1,435 to $2,283. These are patients who are, by definition, critically ill. A $967 increase in expected out-of-pocket exposure per admission, applied across more than half a million discharges annually, translates to a very large aggregate burden.

Heart failure with MCC (DRG 291) saw its gap rise 54.3%, from $1,257 to $1,939, while its share of total payment grew from 11.6% to 16.7%, a 5.1 percentage point increase. For a condition that generates 319,367 Medicare admissions per year, that shift compounds quickly.

Where the Aggregate Burden Is Largest

Per-discharge numbers tell part of the story. Weighted by discharge volume, the picture becomes more concrete.

DRG 871 alone generated $1.31 billion in aggregate beneficiary cost-sharing in 2023. The aggregate burden increase for that single DRG, calculated by applying the per-discharge gap increase to 2023 discharge volume, was $503 million. Heart failure with MCC added another $200 million in aggregate burden increase.

DRG 003 (ECMO or tracheostomy with prolonged mechanical ventilation) is a smaller-volume but extreme case: the per-discharge gap rose from $11,409 to $29,381, an increase of $17,972 per admission. With 6,835 discharges in 2023, the aggregate burden increase for that DRG alone was $123 million.

The Structural Shift Hidden in Percentage Points

The percentage-point change in beneficiary share of total payment is where the structural story becomes clearest. Across the 20 highest-volume DRGs, not one showed a decline in beneficiary cost-sharing as a share of total payment. Every single DRG shifted more of the total payment burden onto patients.

Heart failure with CC (DRG 292) saw the largest percentage increase in the gap itself: 79.7%, from $1,204 to $2,164. Simple pneumonia with CC (DRG 194) saw its beneficiary share of total payment rise 6.1 percentage points, from 19.2% to 25.3%. Cardiac arrhythmia with CC (DRG 309) moved from 21.4% to 27.3%, a 5.9 point shift.

Percutaneous cardiovascular procedures with drug-eluting stent (DRG 247) carried the highest absolute gap in 2023 among high-volume DRGs: $4,112 per discharge, up from $2,640 in 2013. That's a $1,472 increase, or 55.8%, for a procedure that generated nearly 40,000 Medicare discharges in 2023.

The consistency of this pattern across conditions as different as sepsis, hip replacement, cardiac arrhythmia, and gastrointestinal hemorrhage makes it difficult to attribute to any single clinical or coding factor. What it means in practice: a Medicare beneficiary admitted for almost any major inpatient condition in 2023 faced a materially larger share of the total bill than a beneficiary with the same diagnosis a decade earlier.