Room for improvement of diabetes care in the Netherlands
Trends in mortality, cardiovascular complications, and risk factors in type 2 diabetes
Introduction and methods
In the Euro Diabetes Index 2014, the quality of T2DM care in the Netherlands took the second place due to its primary care programs that are well organized (regular check-ups in a multidisciplinary team) . General practitioners (GP)s are the primary treating physicians who treat T2DM patients in the Netherlands. Main criticism by the Euro Diabetes Index 2014 of Dutch diabetes care was the lack of data on CV outcomes.
It is unclear whether changes have occurred in diabetes care and how this has affected outcomes in T2DM patients in the Netherlands. Trends in CV incidence and mortality in T2DM patients compared to diabetes-free individuals between 2008 and 2016 were examined, as well as trends in proportion reaching target goals of risk factors and changes in use of glucose-lowering drugs.
Data were obtained from the PHARMO Database Network. This network links out-patient pharmacy drug dispensing, laboratory test results from primary and secondary care, primary care GP records, secondary care hospitalizations, and mortality records. Also hospitalization data from the Dutch Hospital Data Foundation  was used for accurate dates of CV events. Annual cohorts of T2DM patients with index dates of January 1 of each year were identified between 2008 and 2016. Patients free of diabetes were matched controls to create matched annual cohorts (matching based on age, sex and treating GP).
- 53602 T2DM patients were included in annual cohorts. Proportion of men increased from 51% to 55% between 2008 and 2016 and overall mean age from 66 to 69 years.
- Proportion of T2DM patients with CV morbidity increased from 23% to 37%.
- Antihypertensive drug use of T2DM patients increased from 69% to 74%, statin use from 60% to 68% and platelet aggregation inhibitor use was stable at 31%. Mean levels of LDL-c, blood pressure and HbA1c decreased slightly. Mean BMI was stable at 30 kg/m² during the study period.
- T2DM increased the risk of mortality by 86%, the risk of acute myocardial infarction (AMI) by 69%, congestive heart failure (CHF) by 185%, and stroke by 57%.
- Slowly increasing trends were observed for age-standardised incidence rates for CV events in T2DM (P trend=0.0153 for AMI; P<0.0001 for CHF and stroke) and mortality (P trend <0.0001). RRs did not show clear trends, indicating the increase was proportional in diabetes patients and non-diabetes patients.
- Life years lost to T2DM was 3.5 years at age 55 to just over 1 year at age 80. CVD combined with T2DM resulted in an additional loss of 1.5 years at age 55 and 0.7 years at age 80 compared to T2DM alone.
- Proportion reaching LDL-c goal target rose from 56% in 2009 to 65% in 2016 (P trend <0.0001) For SBP, proportion reaching goal target rose from 57% to 72% (P trend <0.0001), and HbA1c goal attainment rose from 58% to 65% (P trend <0.0001). In 2009, 21% of patients attained all goals, which rose to 33% in 2016 (P trend <0.0001).
- >80% of patients used metformin, which increased slowly over the study period. The proportion using SUs decreased from 50% in 2008 to 43% in 2016. Between 2012 and 2016, a sharp increase in gliclazide use from about 11% to approximately 25% was observed. The proportion of insulin users was approximately 25%, showing a minimal increase over the whole study period. For DPP-4 inhibitors, the proportions increased from 1% in 2008 to 7% in 2013, after which the proportion stabilised. Other glucose-lowering agents were used by only up to 0.5% of patients
- Most used second-line treatment after ≥6 months mono-metformin use SUs (96% in 2008 and 93% in 2016). Within the SU class, the use of gliclazide rose sharply from 19% in 2012 to to 88% of all second-line therapy. The second most-used drug class in second-line therapy was DPP-4 inhibitors.
An analysis of data from the PHARMO Database Network showed that although diabetes care is well organized in the Netherlands, rates for CV events and mortality did not decrease over the study period from 2008 to 2016. Life years lost due to T2DM is 3.5 years at the age of 55 years and in addition with CVD there is an additional loss of 1.5 years. These findings suggest there is room for improvement of management of T2DM patients to obtain better outcomes.