Almost every hospital in the USA has a Dept. of Continuing Medical
Education (CME)that provides lectures and other programs to keep the
physician abreast of the ever changing medical scene. Credits are
awarded on a one for one hr. basis. Most States are requiring doctors
to earn 50 credit hours per year to maintain his/her medical license.
  My question is: has there been any research or studies to confirm
that CME  has improved patient care?

Easy - many examples in the literature:
For example, a study by Rhodes in J Am Coll Surg - 01-APR-2003 p 604, titled:
"Continuing medical education activity and American Board of Surgery
examination performance"
--a study of 278 randomly chosen applicants for surgical
recertification in the year 2000. The study examined such variables as
practice type, career activity, age, gender, other Board
certifications, examination attempts, community size, geographic
region, nationality, and ethnicity.

Author found that of the sample diplomates who took the examination,
10.2% failed. The "Pass" group reported 53% more total CME hours and
38% more AMA Category I CME hours than the "Fail" group. Very strong
statistical analysis of the results of the study supporting the
findings.

Conclusion: There is a strong relationship between CME activity and
performance on the American Board of Surgery Recertification
Examination.

No charge, pardner.