Medicare Part D 2024: brand-name drugs were 15% of claims but 88% of cost, where CMS reports the split

Research question

Generic drugs fill most prescriptions, but brand-name drugs drive most spending. We measured how large that gap was in Medicare's drug benefit in 2024 and how much the brand-name share of prescriptions differs from state to state.

Methodology

PlainDoctor loads the CMS Medicare Part D Prescribers by Provider file for data year 2024 into table prescriber_summary (1,416,883 prescribers, one row per NPI). CMS suppresses the brand and generic split for prescribers with small counts, so this study keeps only the 779,916 rows where brand_claims, generic_claims, brand_cost and generic_cost are all reported. National and state figures come from:

SELECT state, count(*) AS prescribers,
  100.0*sum(brand_claims)/(sum(brand_claims)+sum(generic_claims)) AS brand_claim_pct,
  100.0*sum(brand_cost)/(sum(brand_cost)+sum(generic_cost))       AS brand_cost_pct,
  sum(brand_cost)/sum(brand_claims)     AS cost_per_brand_claim,
  sum(generic_cost)/sum(generic_claims) AS cost_per_generic_claim
FROM prescriber_summary
WHERE brand_claims IS NOT NULL AND generic_claims IS NOT NULL
  AND brand_cost IS NOT NULL AND generic_cost IS NOT NULL
GROUP BY state HAVING prescribers >= 1000
ORDER BY brand_claim_pct DESC;

The national row is the same query without GROUP BY. State is the prescriber's state in the CMS file; 52 jurisdictions have at least 1,000 qualifying prescribers.