New physician-investigators receiving National Institutes of Health research project grants: a historical perspective on the "endangered species".

Context: Although concerns have persisted for decades about the production of new physician clinical scientists and their success in receiving and sustaining research supported by the National Institutes of Health (NIH), no comprehensive analysis documents the experiences of first-time investigators with an MD over a long period.

Objective: To ascertain the perseverance and comparative success of physician-scientists competing for NIH research (R01) grants awarded over 40 years.

Design, Setting, And Participants: A longitudinal, comparative study of all first-time applicants and recipients of NIH R01 grants between 1964 and 2004 stratified by the principal investigators' major degrees (MD, PhD, or MD and PhD) and their proposed involvement in research of humans or human tissues.

Main Outcome Measures: Number of first- and second-time NIH R01 grant applicants and recipients by academic degree and by research type (clinical vs nonclinical).

Results: The annual number of first-time investigators with an MD only as NIH R01 grant applicants remained remarkably stable over 4 decades (41-year mean of 707 [range, 537-983] applicants). Among first-time applicants, those with an MD consistently had less success in obtaining funding (mean annual percentage [MAP], 28%) than either investigators with a PhD (MAP, 31%; P = .03 vs MD only) or both an MD and a PhD (MAP, 34%; P<.001 vs MD only and P = .002 vs PhD only). Among investigators who obtained a first R01 grant, those with an MD were consistently less likely (MAP, 70%) than those with a PhD (MAP, 73%; P = .04 vs MD only) or those with an MD and a PhD (MAP, 78%; P<.001 vs MD only and P = .007 vs PhD only) to obtain a subsequent R01 grant. First-time applicants with an MD were much more likely to propose clinical research (MAP, 67%) than applicants with an MD and a PhD (MAP, 43%) and applicants with a PhD only (39%). First-time applicants with an MD only who proposed clinical research were funded at lower rates than their MD-only counterparts proposing nonclinical research (23% vs 29%, respectively; P<.001).

Conclusions: From 1964-2004, the number of physician-investigators applying for first R01 grants showed little net change. Physician-investigators consistently experienced higher rates of attrition and failure, even after receiving a first R01 grant, and those proposing clinical research were less successful in obtaining funding than physicians proposing nonclinical research.