Comparison of Drug Adherence Rates Among Patients with Seven Different Medical Conditions

Abstract

Study Objective-To compare drug adherence rates among patients with gout, hypercholesterolemia, hypertension, hypothyroidism, osteoporosis, seizure disorders, and type 2 diabetes mellitus by using a standardized approach. Design-Longitudinal study. Data Source-Health care claims data from 2001-2004.Patients-A total of 706,032 adults aged 18 years or older with at least one of the seven medical conditions and with incident use of drug therapy for that condition.Measurements and Main Results-Drug adherence was measured as the sum of the days' supply of drug therapy over the first year observed. Covariates were age, sex, geographic residence, type of health plan, and a comorbidity score calculated by using the Hierarchical Condition Categories risk adjuster. Bivariate statistics and stratification analyses were used to assess unadjusted means and frequency distributions. Sample sizes ranged from 4984 subjects for seizure disorders to 457,395 for hypertension. During the first year of drug therapy, 72.3% of individuals with hypertension achieved adherence rates of 80% or better compared with 68.4%, 65.4%, 60.8%, 54.6%, 51.2%, or 36.8% for those with hypothyroidism, type 2 diabetes, seizure disorders, hypercholesterolemia, osteoporosis, or gout, respectively. Age younger than 60 years was associated with lower adherence across all diseases except seizure disorders. Comorbidity burden and adherence varied by disease. As comorbidity increased, adherence among subjects with osteoporosis decreased, whereas adherence among those with hypertension, hypercholesterolemia, or gout increased. Addon drug therapies and previous experience with taking drugs for the condition increased adherence among subjects with hypertension, type 2 diabetes, hypothyroidism, or seizure disorders but not the other conditions. Our assessment of the published empiric evidence revealed few comparisons of drug nonadherence rates across medical conditions. Nearly all adherence studies have focused on a single disease, and comparisons across studies are difficult given the wide variety of methods used to calculate drug nonadherence rates. 4 The objective of our study was to apply a uniform method for comparing adherence rates across a range of chronic medical conditions that are commonly treated with long-term drug therapy. Conclusion-This Methods Study Population and Data SourcesThe study sample included approximately 1.3 million individuals aged 18 years or older who had a diagnosis of gout, hypercholesterolemia, hypertension, hypothyroidism, osteoporosis, seizure disorders, or type 2 diabetes during the study period of [2001][2002][2003][2004]. These conditions were selected because they are chronic, because they commonly occur in adults, and because regular and persistent drug therapy is recommended as treatment. In addition, the subjects must have started new drug therapy for their condition between January 1, 2002, and December 31, 2003. Table 1 lists the diagnostic codes and drug therapies for these disorders.Our analysis focused on rec...

Is there an impatience genotype leading to non-adherence to long-term therapies?

“…This hypothesis is consistent with: (1) the frequent association between several manifestations of nonadherence and smoking and alcohol habits: for instance, smoking and excessive alcohol consumption are independent predictors of low practice of self-monitoring of blood glucose in diabetic patients [39]; (2) the effect of young age on non-adherence in chronic diseases [7]; (3) the frequency of non-adherence in teenagers (an experimental study showed that adolescents and people in their twenties have more difficulties in finding similarities between them now and them in the future than older people [40]); (4) the fact that the level of maturity is associated with adherence to immunosuppressive drugs in adolescent and young adults following heart transplantation [41]; (5) data from fMRI studies, providing the evidence that the balance between frontal and limbic circuitries is relatively late maturing during the brain development from childhood to adult age [42,43]: it is tempting (even if hazardous) to see an explanation of a risk in teenagers, not only for addiction, but also for poor adherence; (6) the effect of social deprivation on non-adherence to medication [44]: a shorter temporal horizon was found to be associated to a lower income [38]; (7) the effect of education on adherence to medication and other health behaviours [45]: a stronger future orientation of women, who asked more frequently for BRCA1/2 screening and mammography, was seen in women who had higher levels of education [35]; and finally (8), this explanation may represent a common link leading to a clustering of preventive behaviours in some individuals, this concept of 'healthy adherer' explaining the puzzling observation that adherence to a placebo is associated with a decrease in mortality [46].…”

“…A recent study evaluated non-adherence in seven chronic diseases: hypertension, hypothyroidism, type 2 diabetes, seizure disorders, hypercholesterolaemia, osteoporosis and gout [7]. Sample sizes ranged from 4,984 patients for seizure disorders to 457,395 for hypertension.…”

“…These observations contradict the common view that non-adherence is especially frequent in 'silent' diseases such as diabetes. Younger age (<60 years) has also been associated with lower adherence for all diseases except seizure disorders [7], suggesting that the chronic character of the disease, i.e. its potential future duration, is more important than the fact that it may be painful.…”

Target Serum Urate: Do Gout Patients Know Their Goal?

“…Importantly, this possibility suggests that our estimate of SU goal knowledge, although quite low, is likely higher than would be seen in a broader patient population. Our study also indicated high levels of medication adherence for both questionnaire responders and nonresponders relative to other recent studies (15,(37)(38)(39)(40)(41). The PDC values in our study are higher than in other studies, likely due to the high proportion of prevalent users in our cohort and the use of mailed prescriptions in the VA system.…”

Self-report measures of medication adherence behavior: recommendations on optimal use

“…Inadequate adherence to medications is unfortunately widespread across ages, health conditions, and medication regimens [10,[25][26][27]]. DiMatteo's [27] seminal review of over 500 adherence studies spanning multiple chronic conditions and medication classes reported an average medication nonadherence rate of 24.8 %.…”