Impact of Socioeconomic Factors and Gender on Refill Adherence and Persistence to Lipid-Lowering Therapy in Type 1 Diabetes

INTRODUCTION

Lipid-lowering therapy (LLT) reduces the risk of cardiovascular disease (CVD) in patients with type 1 diabetes (T1D). However, socioeconomic factors and gender may have an impact on the adherence to and non-persistence with LLT.

METHODS

This was a nationwide register-based cohort study that included 6192 individuals with T1D aged ≥ 18 years who were registered in the Swedish National Diabetes Register and had initiated novel use of LLT. Information on socioeconomic parameters (source: Statistics Sweden) and comorbidity (source: National Patient Register) was collected. The individuals were followed for 36 months, and adherence to LLT was analyzed according to age, socioeconomics and gender. The medication possession ratio (MPR; categorized into ≤ 80% and > 80%) and non-persistence (discontinuation) with medication was calculated after 18 and 36 months.

RESULTS

Individuals older than 53 years were more adherent to LLT (MPR > 80%) than those younger than 36 years (odds ratio [(OR] 1.30, p < 0.0001) at 36 months. Women were more adherent and less prone to discontinue LLT at 18 months (OR 1.05, p = 0.0005 and OR 0.95, p = 0.0004, respectively), but not at 36 months. Divorced individuals were less adherent than married ones (OR 0.93, p = 0.0005) and discontinued LLT more often than the latter (OR 1.06, p = 0.003). Education had no impact on adherence, but individuals with higher incomes discontinued LLT less frequently than those with lower incomes. Individuals with a country of origin other than Sweden discontinued LLT more often.

CONCLUSION

Lower adherence to LLT in individuals with T1D was associated with male gender, younger age, marital status and country of birth. These factors should be considered when evaluating adherence to LLT in clinical practice, with the aim to help patients achieve full cardioprotective treatment.

Adherence to lipid-lowering therapy and risk for cardiovascular disease and death in type 1 diabetes mellitus: a population-based study from the Swedish National Diabetes Register

Dyslipidemia is an important modifiable risk factor and lipid-lowering treatment (LLT) is essential to reduce the risk of cardiovascular disease (CVD). Studies in type 2 diabetes indicate that low adherence to statin therapy is a barrier to reach full protective potential, and less is known in type 1 diabetes (T1D). The aim was to assess risk of CVD by adherence and nonpersistence to LLT in T1D.  METHOD: A population-based study with a retrospective longitudinal design was conducted between 2006 and 2010, with follow-up until December 2013. In total, 6192 adult individuals with T1D, initiating LLT between 2006 and 2010, were included. Information on LLT, socioeconomic characteristics, comorbidities and cardiovascular events were collected. After 18 months, refill adherence was estimated by calculating medication possession ratio (MPR). Nonpersistence was defined as being without medicines on hand for at least 180 days. Individuals were thereafter followed until CVD, death or end of follow-up in December 2013. Cox regression analyses were performed to assess adherence level and nonpersistence of LLT as predictor of CVD. Analyses were adjusted for cardiovascular risk factors and socioeconomic status.   RESULTS: Mean MPR was 72%, 52% of the participants had an MPR above 80% and 27% discontinued LLT. There were 637 nonfatal and 58 fatal CVD events, mean follow-up 3.6 and 3.9 years, respectively. MPR above 80% was associated with reduced risk for nonfatal CVD compared with lower MPR, HR 0.78 (95% CI 0.65 to 0.93)). For fatal CVD, results indicated a negative effect of high adherence but the association did not reach statistical significance, HR 1.96 (0.96 to 4.01). Individuals discontinuing LLT had higher risk of nonfatal CVD, HR 1.43 (95% CI 1.18 to 1.73).  CONCLUSIONS/INTERPRETATION: In T1D, the risk for nonfatal CVD was lower among individuals with high adherence and higher among those discontinuing LLT within 18 months. It is important to evaluate and emphasize adherence to prescribed LLT at clinical visits to achieve treatment goals and reduce the risk of CVD.

Characteristics and Prognosis in Women and Men With Type 1 Diabetes Undergoing Coronary Angiography: A Nationwide Registry Report

OBJECTIVE

To describe sex aspects on extent of coronary artery disease (CAD) and prognosis in a contemporary population with type 1 diabetes.

RESEARCH DESIGN AND METHODS

All patients undergoing coronary angiography, 2001-2013, included in the Swedish Coronary Angiography and Angioplasty Registry and the Swedish National Diabetes Register as type 1 diabetes were followed for mortality until 31 December 2013. The coronary angiogram was classified into normal, one-vessel disease, two-vessel disease, three-vessel disease, and left main stem disease.

RESULTS

In all, 2,776 patients (42% women) with mean age 58 years (SD 11) were followed for 7.2 years (SD 2.2). Diabetes duration was longer in women (37 ± 14 vs. 34 ± 14 years in men; P < 0.001), who also had more retinopathy (68% vs. 65%; P = 0.050), whereas microalbuminuria was less common (41% vs. 51%; P < 0.001). Indications for coronary angiography did not substantially differ in women and men. The extent of CAD was somewhat less severe in women (normal angiogram 23.5% vs. 19.1%, three-vessel and left main stem disease 34.5% vs. 40.4%; P = 0.002), whereas mortality did not differ (adjusted hazard ratio 1.03 [95% CI 0.88-1.20]; P = 0.754). The standard mortality ratio for women the first year was 7.49 (5.73-9.62) and for men was 4.58 (3.60-5.74).

CONCLUSIONS

In patients with type 1 diabetes admitted for coronary angiography, the extent of CAD was almost similar in women and men, and total long-term mortality did not differ. Type 1 diabetes was associated with higher mortality risk in women than in men when compared with the general population. These data support that type 1 diabetes attenuates the cardiovascular risk difference seen in men and women in the general population.

Association between refill adherence to lipid-lowering medications and the risk of cardiovascular disease and mortality in Swedish patients with type 2 diabetes mellitus: a nationwide cohort study

OBJECTIVES

To analyse the association between refill adherence to lipid-lowering medications, and the risk of cardiovascular disease (CVD) and mortality in patients with type 2 diabetes mellitus.

DESIGN

Cohort study.

SETTING

National population-based cohort of Swedish patients with type 2 diabetes mellitus.

PARTICIPANTS

86 568 patients aged ≥18 years, registered with type 2 diabetes mellitus in the Swedish National Diabetes Register, who filled at least one prescription for lipid-lowering medication use during 2007-2010, 87% for primary prevention.

EXPOSURE AND OUTCOME MEASURES

Refill adherence of implementation was assessed using the medication possession ratio (MPR), representing the proportion of days with medications on hand during an 18-month exposure period. MPR was categorised by five levels (≤20%, 21%-40%, 41%-60%, 61%-80% and >80%). Patients without medications on hand for ≥180 days were defined as non-persistent. Risk of CVD (myocardial infarction, ischaemic heart disease, stroke and unstable angina) and mortality by level of MPR and persistence was analysed after the exposure period using Cox proportional hazards regression and Kaplan-Meier, adjusted for demographics, socioeconomic status, concurrent medications and clinical characteristics.

RESULTS

The hazard ratios for CVD ranged 1.33-2.36 in primary prevention patients and 1.19-1.58 in secondary prevention patients, for those with MPR ≤80% (p<0.0001). The mortality risk was similar regardless of MPR level. The CVD risk was 74% higher in primary prevention patients and 33% higher in secondary prevention patients, for those who were non-persistent (p<0.0001). The mortality risk was 6% higher in primary prevention patients and 18% higher in secondary prevention patients, for non-persistent patients (p<0.0001).

CONCLUSIONS

Higher refill adherence to lipid-lowering medications was associated with lower risk of CVD in primary and secondary prevention patients with type 2 diabetes mellitus.

Refill adherence and persistence to lipid-lowering medicines in patients with type 2 diabetes: A nation-wide register-based study

Purpose

This study aimed to describe and compare refill adherence and persistence to lipid‐lowering medicines in patients with type 2 diabetes by previous cardiovascular disease (CVD).

Methods

We followed 97 595 patients (58% men; 23% with previous CVD) who were 18 years of age or older when initiating lipid‐lowering medicines in 2007–2010 until first fill of multi‐dose dispensed medicines, death, or 3 years. Using personal identity numbers, we linked individuals' data from the Swedish Prescribed Drug Register, the Swedish National Diabetes Register, the National Patient Register, the Cause of Death Register, and the Longitudinal Integration Database for Health Insurance and Labour Market Studies. We assessed refill adherence using the medication possession ratio (MPR) and the maximum gap method, and measured persistence from initiation to discontinuation of treatment or until 3 years after initiation. We analyzed differences in refill adherence and persistence by previous CVD in multiple regression models, adjusted for socioeconomic status, concurrent medicines, and clinical characteristics.

Results

The mean age of the study population was 64 years, 80% were born in Sweden, and 56% filled prescriptions for diabetes medicines. Mean MPR was 71%, 39% were adherent according to the maximum gap method, and mean persistence was 758 days. Patients with previous CVD showed higher MPR (3%) and lower risk for discontinuing treatment (12%) compared with patients without previous CVD (P < 0.0001).

Conclusions

Patients with previous CVD were more likely to be adherent to treatment and had lower risk for discontinuation compared with patients without previous CVD.

Mortality and extent of coronary artery disease in 2776 patients with type 1 diabetes undergoing coronary angiography: A nationwide study

Background In a modern perspective there is limited information on mortality by affected coronary vessels assessed by coronary angiography in patients with type 1 diabetes. The aim of the present study was to characterise distribution of coronary artery disease and impact on long-term mortality in patients with type 1 diabetes undergoing coronary angiography. Design The design of this research was a nationwide population-based cohort study. Methods Individuals ( n = 2776) with type 1 diabetes undergoing coronary angiography 2001-2013 included in the Swedish National Diabetes Registry and Swedish Coronary Angiography and Angioplasty Registry were followed for mortality until 31 December 2013 (mean 7.1 years). In 79% the indication was stable or acute coronary artery disease. Coronary artery disease was categorised into normal (21%), one- (23%), two- (18%), three- (29%) and left main-vessel disease (8%). Results Mean age was 57 years and 58% were male. Mean diabetes duration was 35 years, glycated haemoglobin was 67 mmol/mol and 44% had normal or one-vessel disease. In multivariate Cox proportional analyses hazard ratio for mortality compared with normal findings was 1.09 (95% confidence interval 0.80-1.48) for one, 1.43 (1.05-1.94) for two, 1.47 (1.10-1.96) for three and 1.90 (1.35-2.68) for left main-vessel disease. Renal failure 2.29 (1.77-2.96) and previous heart failure 1.76 (1.46-2.13) were highly associated with mortality. Standard mortality ratio the first year was 5.55 (4.65-6.56) and decreased to 2.80 (2.18-3.54) after five years. Conclusions In patients with type 1 diabetes referred for coronary angiography mortality is influenced by numbers of affected coronary vessels. The overall mortality rate was higher compared with the general population. These results support early intensive prevention of coronary artery disease in this population.

Association Between Use of Lipid-Lowering Therapy and Cardiovascular Diseases and Death in Individuals With Type 1 Diabetes

OBJECTIVE

To evaluate the effect of lipid-lowering therapy (LLT) in primary prevention on cardiovascular disease (CVD) and death in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We used the Swedish National Diabetes Register (NDR) to perform a propensity score-based study. Propensity scores for treatment with LLT were calculated from 32 baseline clinical and socioeconomic variables. The propensity score was used to estimate the effect of LLT in the overall cohort (by stratification). We estimated risk of acute myocardial infarction, stroke, coronary heart disease, and cardiovascular and all-cause mortality in individuals with and without LLT using Cox regression. A total of 24,230 individuals included in 2006-2008 NDR with type 1 diabetes without a history of CVD were followed until 31 December 2012; 18,843 were untreated and 5,387 treated with LLT (97% statins). The mean follow-up was 6.0 years.

RESULTS

The propensity score allowed balancing of all 32 covariates, with no differences between treated and untreated after accounting for propensity score. Hazard ratios (HRs) for treated versus untreated were as follows: cardiovascular death 0.60 (95% CI 0.50-0.72), all-cause death 0.56 (0.48-0.64), fatal/nonfatal stroke 0.56 (0.46-0.70), fatal/nonfatal acute myocardial infarction 0.78 (0.66-0.92), fatal/nonfatal coronary heart disease 0.85 (0.74-0.97), and fatal/nonfatal CVD 0.77 (0.69-0.87).

CONCLUSIONS

This observational study shows that LLT is associated with 22-44% reduction in the risk of CVD and cardiovascular death among individuals with type 1 diabetes without history of CVD and underlines the importance of primary prevention with LLT to reduce cardiovascular risk in type 1 diabetes.

LDL cholesterol is not a good marker of cardiovascular risk in Type 1 diabetes

AIM

LDL cholesterol (LDL-C) is considered an important cardiovascular disease (CVD) risk factor. Less is known in Type 1 diabetes. We assessed LDL-C and total cholesterol to HDL cholesterol ratio (TC/HDL-C) as predictors of CVD in Type 1 diabetes.

METHODS

The study monitored 30 778 people with Type 1 diabetes, baseline 2003-2006, to 31 December 2011. Cox regression analyses were performed with LDL-C and TC/HDL-C as predictors of fatal/non-fatal CVD. Models were adjusted for traditional CVD risk factors.

RESULTS

Hazard ratios (HR) (with 95% CI) per 1 mmol/l increase in LDL-C for CVD were 1.09 (1.01-1.18) in people without lipid-lowering medication and 1.02 (0.95-1.09) in people with lipid-lowering medication (P = 0.02 and 0.65). In people aged 40 years or older having a CVD risk factor, and in people with a history of CVD, HR was 1.07 (0.99-1.16) and 1.02 (0.92-1.13) (P = 0.07 and 0.66). HR per 1 unit increase in TC/HDL-C was 1.12 (1.05-1.20) in people without lipid-lowering medication and 1.08 (1.02-1.15) in people with lipid-lowering medication (P < 0.001 and 0.01). For people aged 40 or older and people with a history of CVD, HR was 1.16 (1.09-1.24) and 1.04 (0.95-1.14) (P < 0.001 and 0.43). Broken down into octiles, LDL-C was not a significant predictor of CVD in any group. Higher octiles of TC/HDL-C were significant predictors for CVD in people without lipid-lowering medication and in those aged 40 years or older.

CONCLUSION

In this study of people with Type 1 diabetes in clinical practice, LDL-C was not a good predictor of CVD. We found no support for an LDL-C cut-off point < 2.6 mmol/l. TC/HDL-C seems more reliable as a marker for CVD risk when considering primary prevention.