Relationship between earlier and later mammography screening - California Medicare, 1992 through 1994

Regular screening mammography is recommended to reduce breast cancer mortal ity. Although predictors of mammography have been studied, factors that inf luence adherence to guidelines are less understood. We examined the relatio nship between an index mammogram and subsequent mammograms among California Medicare beneficiaries. Medicare billing data for 1992, 1993, and 1994 wer e used to estimate the association between screening mammography in 1992 an d subsequent screening in 1993 or 1994, We found that women with a 1992 mam mogram were more than twice as likely to have a mammogram in 1993 or 1994 t han women without a 1992 mammogram (relative risk = 2.58; 95% confidence in terval, 2.57-2.59). This relationship was somewhat stronger for black women compared with white women and increased with age. Although further study o f regular screening patterns is needed, these findings provide some evidenc e that encouraging a single mammogram may lead to continued adherence.