Pharmacoepidemiological profiles of oral hypoglycemic agents among 28,773 Chinese patients with diabetes

Treatment discontinuation of oral hypoglycemic agents and healthcare utilization among patients with diabetes

AIMS

To investigate the discontinuation of oral antihyperglycemic agents (OHA), and examine factors associated with OHA discontinuation, and the effect of OHA discontinuation on glycemic control and healthcare utilization among diabetes patients prescribed dual OHA therapy.

METHODS

We identified 23,612 adult patients aged >18years with a diagnosis of type 2 diabetes who initiated dual OHA therapy between 1/1/2005 and 6/30/2010. The date of initiation of the second OHA was defined as the index date. Discontinuation was defined as a gap >1.5 times the last days' supply without subsequent reinitiation.

RESULTS

Over 24months, 16.9% discontinued 1 OHA and 9.2% discontinued both. Patients who discontinued were more likely to be female, younger, Black or of Hispanic ethnicity, have more comorbidities, higher medication co-pays, start both OHAs together, have higher healthcare utilization before the index date and less likely to use prescription mail order compared with patients who did not discontinue. In multivariable regression models, patients who discontinued were more likely to be hospitalized or have emergency department visits during follow-up.

CONCLUSIONS

Discontinuation of OHAs is common among patients with diabetes and is associated with several patient factors and increased healthcare utilization. Future research should further examine reasons for OHA discontinuation.

Meta-analysis of studies examining medication adherence, persistence, and discontinuation of oral antihyperglycemic agents in type 2 diabetes

OBJECTIVE

To estimate overall rates of adherence, persistence, and discontinuation for patients with type 2 diabetes mellitus (T2DM) prescribed oral antihyperglycemic agents (OAHAs) by combining results of published studies.

RESEARCH DESIGN AND METHODS

A systematic literature review was conducted to identify articles published in English over the last 10 years evaluating the use of OAHAs for the treatment of T2DM. Databases searched included PubMed/MEDLINE, EMBASE, and the Cochrane Library. Seventy studies reporting adherence, persistence or discontinuation were identified by two independent reviewers and 40 reported relevant endpoints for the analysis. Outcomes included: (1) mean adherence defined as the average medication possession ratio (MPR); (2) proportion of adherent patients (MPR ≥ 80%); (3) discontinuation; and (4) persistence. Adherence and persistence were reported in observational studies only. Discontinuation was examined separately in randomized controlled trials (RCTs) and observational studies. Meta-analyses were conducted using both fixed and random effects models. When meta-analysis was not appropriate for a given outcome, descriptive statistics were provided.

RESULTS

The pooled mean MPR (95% confidence interval [CI]) was 75.3% (68.8%-81.7%; n = 13) and the proportion of adherent patients (95% CI) was 67.9% (59.6%-76.3%; n = 12). The discontinuation rate (95% CI) in RCTs was 31.8% (17.0%-46.7%; n = 7). Persistence and discontinuation were not assessed via meta-analysis for observational studies due to the limited number of available studies and differences in outcome definitions. In these studies, persistence estimates ranged from 41.0% to 81.1%, with a mean (95% CI) of 56.2% (46.1%-66.3%; n = 6), while discontinuation estimates ranged from 9.9% to 60.1%, with a mean (95% CI) of 31.4% (17.6%-45.3%; n = 6).

LIMITATIONS

Limitations include (1) the use of MPR as a proxy for adherence, (2) limited number of studies available, and (3) observed heterogeneity.

CONCLUSION

The results of the analysis demonstrate that medication adherence, persistence, and discontinuation rates are suboptimal in patients with T2DM prescribed OAHAs.

Association between the 8-item Morisky medication adherence scale (MMAS-8) score and glycaemic control among Chinese diabetes patients

Adherence with oral hypoglycaemic agent is crucial to achieve optimal glycaemic control. The 8-item Morisky Medication Adherence Scale (MMAS-8) has been frequently used, yet the association between MMAS-8 score and glycaemic control among Chinese diabetes patients is largely unknown. Two general out-patient clinics were randomly selected in a district with socio-demographic characteristics representative of the entire Hong Kong population. A consecutive sample of adult type-2 diabetes patients currently taking oral hypoglycaemic agents was included. The glycaemic control was reflected by the level of hemoglobin A1c (HbA1c) taken within the previous 6 months. Factors associated with poor glycaemic control (HbA1c ≥ 7.0%) were evaluated by linear regression analysis. From 565 eligible Chinese patients with an average age of 63.2 years (SD 9.7) and male proportion of 46.5%, the average HbA1c was 7.1% (SD 1.1%), and 52.0% had poor glycaemic control. The proportion of poor medication adherence (MMAS-8 ≤ 6) was 32.2%. After controlling for socio-demographics, lifestyle, medication use, and health characteristics, the MMAS-8 score was correlated with better glycaemic control (beta -0.095; 95%CI -0.164 to -0.026, P = .007). The MMAS-8 score had a weak and negative correlation with HbA1c level. The instrument should be applied with caution when predicting glycaemic control in clinical practice.

The association between multimorbidity and poor adherence with cardiovascular medications

Multimorbidity, defined as the presence of two or more chronic conditions, leads to a substantial public health burden. This study evaluated its association with adherence with cardiovascular medications in a Chinese population. A proportional stratified sampling was adopted to draw a representative sample of residents living in Henan Province, China. Interviewer-administered surveys were conducted by trained researchers. The outcomes included the number of chronic medical conditions, adherence with long-term medications (MMAS-8), and depressive symptoms (CESD-20). Binary logistic regression analysis was conducted to evaluate if medication adherence was associated with the presence of multimorbidity. From a total of 3866 completed surveys, the proportion of subjects having 0, 1 and ≥2 chronic conditions was 62.6%, 23.8% and 13.5%, respectively. Among 27.6% who were taking chronic medications, 66.6% had poor medication adherence (MMAS-8 score≤6). From binary logistic regression analysis, subjects with poor medication adherence were significantly associated with multimorbidity (adjusted odds ratio [AOR]: 1.35, 95% C.I. 1.02-1.78, p=0.037). Other associated factors included older age (AOR=1.04, 95% C.I. 1.03-1.05, p<0.001), smoking (AOR=1.63, 95% C.I. 1.16-2.30, p=0.005), family history of hypertension (AOR=1.51, 95% C.I. 1.19-1.93, p=0.001), and fair to poor self-perceived health status (AOR=2.15, 95% C.I. 1.69-2.74, p<0.001). Using medication adherence as the outcome variable, multimorbidity was significantly associated with poor drug adherence (AOR=1.34, 95% C.I. 1.02-1.77, p=0.037). Multimorbidity was associated with poorer medication adherence. This implies the need for closer monitoring of the medication taking behavior among those with multiple chronic conditions.