Methods
Source of Data
Medco Health Solutions Inc. (Franklin Lakes, NJ), one of the largest pharmacy benefit managers in the United States, administers drug benefits to more than 65 million people on behalf of its clients, which generally include employers, government agencies, health plans, unions, and managed-care organizations. This study used Medco’s pharmacy claims database, which contains deidentified eligibility and pharmacy claims information for medications obtained from mail and retail pharmacies through a Medco member’s pharmacy benefit. For each member, the database contains sex, date of birth, and dates of benefit eligibility. For each medication claim, the database contains medication name, date of fill, formulation (eg, oral, transdermal, vaginal, and injectable), dose, quantity, days of supply, and American Medical Association prescriber specialty code.
Study Populations
Study populations were identified for each calendar year from 2000 to 2009. Women who were 50 years and older at the start of the calendar year with continuous pharmacy benefits during the entire 12-month period were included in the study population for that year. Because the analysis focused on annual period prevalence rates, a woman was included in the study population for every year that she met the above eligibility criteria.
Hormone Therapy
HT included estrogen therapy and combined estrogen/ progesterone therapy and the following formulations: oral, transdermal, vaginal, and injectable. Hormonal contraceptives were not included. Dose per day was calculated using the quantity, strength of estrogen, and days of supply dispensed. Dose ranges were then further classified as high, standard, or low, based on existing industry definitions (see Table, Supplemental Digital Content 1, http://links.lww.com/MENO/A24).
Prevalence and Incidence
Prevalence was defined as the proportion of women in a year’s study population who were prescribed any HT that year. Incidence was defined as a proportion of women in a given study year, with no claims for HT in the previous year, who initiated HT during the study year. The incidence analysis only included women who were continuously eligible for pharmacy benefits during the entire study year and the preceding 12 months. Prevalence and incidence of HT use was evaluated in five age groups (50-54, 55-59, 60-64, 65-74, and ≥75 y).
Prescriber Specialty
The specialty of the prescriber for each HT prescription was determined using American Medical Association specialty codes. Women who received HT prescriptions in a given study year were classified as receiving them from one or more of the following specialties: Gynecology, Family Practice/ Internal Medicine/General Practice (FP/IM/GP), or other. All descriptive analyses were conducted using SAS version 9.1 (SAS Institute Inc., Cary, NC).