The present study involved the analyses of the Texas Medicaid prescription claims data. The population studied was made up of subjects between 10 and 18 years who had at least 2 prescriptions of the same oral antidiabetic (OAD) medication from January 1, 2006 through December 31, 2009. Twelve months’ data for each subject were analyzed. The main aim of the study was to describe OAD medication use patterns in the study population, assess trends in Medication Possession Ratio (MPR) and persistence in the study population and determine the relationship between age and MPR and between age and persistence while controlling for covariates. Results of the descriptive statistics, multiple and logistic regression analyses are reported. The average age (± SD) of the 3,109 eligible subjects was 14 (± 2) years; minority populations made up the majority (87%) of the population; 67% of the population were females; and 91% were on the OAD metformin. The overall mean MPR (± SD) for the population was 45% (± 27). A significant negative relationship between MPR and age was reported while controlling for covariates (p<0.0001). Among the covariates, white race and male were significantly associated with a higher MPR, holding other variables constant. When adherence was dichotomized (MPR < 80% and MPR >= 80%), logistic regression analysis also found that age was significantly and negatively related to MPR (p < 0.0001). In addition, the white race and male were again significantly related to a higher level of adherence, holding other variables constant. The overall mean days to non-persistence (± SD) was 108 days (± 86). Persistence was significantly and negatively associated with age, holding other variables constant (p < 0.0001). Among the covariates, white race was significantly related to longer persistence. In conclusion, adherence and persistence are generally low in the study population. Age, gender and race were significantly associated with adherence. Being younger, male, and white were significantly associated with a higher level of adherence, while being younger and white were significantly associated with longer persistence. Healthcare providers therefore need to intensify efforts to improve adherence in pediatric patients especially those at the brink of adulthood. / text

The present study is a retrospective cohort analysis which sought to examine adherence to medications used in managing painful diabetic peripheral neuropathy (PDPN) and to determine their association with oral antidiabetic (OAD) medication adherence using the Texas Medicaid prescription claims database. The study objectives were to: 1) provide a description of PDPN and OAD medication use among the study subjects; 2) determine if PDPN medication adherence differs among individual PDPN agents (i.e., tricyclic antidepressants, gabapentin, pregabalin and duloxetine); 3) determine if pre-index OAD and post-index OAD medication adherence differs among mono, dual, and triple OAD therapies; and 4) determine if PDPN medication adherence is related to post-index OAD medication adherence while controlling for covariates. Study participants were adult (≥18 years) Medicaid beneficiaries prescribed OAD and PDPN medications. The index date was the first PDPN prescription. Data were extracted from June 1, 2003 to October 31, 2009 and prescription claims were analyzed over an 18-month study period (i.e., 6 months pre-index and 12 months post index period). Medication possession ratio (MPR) was used as a proxy measure of medication adherence. An MPR less than 80 percent was regarded as being non-adherent to prescribed medication, while an MPR greater than or equal to 80 percent was regarded as being adherent to prescribed medication. Objective 1 was addressed using descriptive statistics (i.e., mean, standard deviation, frequency). Univariate analysis (ANOVA) was employed to address Objectives 2 and 3. Multivariate analyses (i.e., multiple linear regression and logistic regression) were conducted to address Objective 4. For the logistic regression MPR was dichotomized at the cut-off value of 80 percent. A total of 4,277 patients met the study’s inclusion criteria. The overall mean MPR (±SD) for PDPN medications was 75.4 percent (±23.9). Mean MPR (±SD) was highest for duloxetine (85.6% ±18.2) and was lowest for pregabalin (69.4% ±24.9). Mean MPR differed significantly among individual PDPN medications (p<0.0001). The overall mean MPR (±SD) for OAD medications in the pre and post-index period was 73.0 percent (±24.3) and 64.5 percent (±25.6) respectively. In both pre and post-index periods, mean MPR differed significantly among mono, dual, and triple OAD therapies (p<0.0001). In the pre-index period, mean MPR (±SD) was highest for monotherapy users (75.4% ±24.7) and was lowest for triple therapy users (63.9% ±22.9). Similarly, mean MPR (±SD) was highest for monotherapy users (69.0% ±26.1) and was lowest for triple therapy users (52.9% ±21.8) in the post-index period. After controlling for the covariates, PDPN adherence (i.e., MPR) was statistically significant (p<0.0001) and positively related to post-index OAD adherence (i.e., MPR). PDPN patients who were non-adherent (i.e., MPR<80%) to their PDPN medications (or neuropathic pain medications), compared to those who were adherent (MPR≥80%), were significantly less likely to be adherent to their OAD medications [Odds Ratio (OR) = 0.626, 95% CI=0.545-0.719]. In addition, post-index OAD adherence (i.e., MPR) did not differ significantly (p>0.05) when pregabalin, duloxetine and gabapentin users were individually compared to tricyclic antidepressants users. In conclusion, PDPN patients who were adherent (i.e., MPR≥80%) to their PDPN medications, compared to those who were not adherent (i.e., MPR<80%), were more adherent to their OAD medications. Also, adherence to OAD medications was independent of the type of PDPN medication used. PDPN patients need to be educated regularly that neuropathic pain medications only relieve the pain associated with the neuropathy but achieving adequate glycemic control remains the only established approach for slowing down the progression of the neuropathy and other complications associated with the diabetes. / text