Benchmarking by HbA1c in a national diabetes quality register--does measurement bias matter?

Intensified follow-up of patients with type 1 diabetes and poor glycaemic control: a multicentre quality improvement collaborative based on data from the Norwegian Diabetes Register for Adults

BACKGROUND

Patients with type 1 diabetes mellitus (T1DM) and poor glycaemic control are at high risk of developing microvascular and macrovascular complications. The aim of this study was to determine if a quality improvement collaborative (QIC) initiated by the Norwegian Diabetes Register for adults (NDR-A) could reduce the proportion of patients with T1DM with poor glycaemic control (defined as glycated haemoglobin (HbA1c)≥75 mmol/mol) and reduce mean HbA1c at participating clinics compared with 14 control clinics.

METHOD

Multicentre study with controlled before and after design. Representatives of 13 diabetes outpatient clinics (n=5145 patients with T1DM) in the intervention group attended four project meetings during an 18-month QIC. They were required to identify areas requiring improvement at their clinic and make action plans. Continuous feedback on HbA1c outcomes was provided by NDR-A during the project. In total 4084 patients with type 1 diabetes attended the control clinics.

RESULTS

Between 2016 and 2019, the overall proportion of patients with T1DM and HbA1c≥75 mmol/mol in the intervention group were reduced from 19.3% to 14.1% (p<0.001). Corresponding proportions in the control group were reduced from 17.3% (2016) to 14.4% (2019) (p<0.001). Between 2016 and 2019, overall mean HbA1c decreased by 2.8 mmol/mol (p<0.001) at intervention clinics compared with 2.3 mmol/mol (p<0.001) at control clinics. After adjusting for the baseline differences in glycaemic control, there were no significant differences in the overall improvement in glycaemic control between intervention and control clinics.

CONCLUSIONS

The registry linked QIC did not result in a significantly greater improvement in glycaemic control at intervention clinics compared with control clinics. However, there has been a sustained improvement in glycaemic control and importantly a significant reduction in the proportion of patients with poor glycaemic control at both intervention and control clinics during and after the QIC time frame. It is possible that some of this improvement may be due to a spillover effect from the QIC.

HbA1c and biomarkers of diabetes mellitus in Clinical Chemistry and Laboratory Medicine: ten years after

Since its discovery in the late 1960s, HbA_1c has proven to be a major biomarker of diabetes mellitus survey and diagnosis. Other biomarkers have also been described using classical laboratory methods or more innovative, non-invasive ones. All biomarkers of diabetes, including the historical glucose assay, have well-controlled strengths and limitations, determining their indications in clinical use. They all request high quality preanalytical and analytical methodologies, necessitating a strict evaluation of their performances by external quality control assessment trials. Specific requirements are needed for point-of-care testing technologies. This general overview, which describes how old and new tools of diabetes mellitus biological survey have evolved over the last decade, has been built through the prism of papers published in Clinical Chemistry and Laboratory Medicine during this period.

Setting analytical performance specifications using HbA1c as a model measurand

Analytical performance specifications (APS) for measurands describe the minimum analytical quality requirements for their measurement. These APS are used to monitor and contain the systematic (trueness/bias) and random errors (precision/imprecision) of a laboratory measurement to ensure the results are "fit for purpose" in informing clinical decisions about managing a patient's health condition. In this review, we highlighted the wide variation in the setting of APS, using different levels of evidence, as recommended by the Milan Consensus, and approaches. The setting of a priori defined outcome-based APS for HbA1c remains challenging. Promising indirect alternatives seek to link the clinical utility of HbA1c and APS by defining statistical confidence for interpreting the laboratory values, or through simulation of clinical performance at varying levels of analytical performance. APS defined based on biological variation estimates in healthy individuals using the current formulae are unachievable by nearly all routine laboratory methods for HbA1c testing. On the other hand, the APS employed in external quality assurance programs have been progressively tightened, and greatly facilitate the improved quality of HbA1c testing. Laboratories should select the APS that fits their intended clinical use and should document the data and rationale underpinning those selections. Where possible common APS should be adopted across a region or country to facilitate the movement of patients and patient data across health care facilities.

National diabetes registries: do they make a difference?

AIMS

The global epidemic of diabetes mellitus continues to expand, including its large impact on national health care. Measuring diabetes outcomes and their causes of variation highlights areas for improvement in care and efficiency gains; large registries carry this potential. By means of a systematic review, we aimed to give an overview of national registries worldwide by quantifying their data and assessing their influence on diabetes care.

METHODS

The literature on MEDLINE up to March 31, 2020, was searched, using keywords diabetes mellitus, national, registry, registration, and/or database. National disease-specific registries from corresponding articles were included. Database characteristics and clinical variables were obtained. All registries were compared to the ICHOM standard set of outcomes.

RESULTS

We identified 12 national clinical diabetes registries, comprising a total of 7,181,356 diabetic patients worldwide. Nearly all registries recorded weight, HbA1c, lipid profile, and insulin treatment; the recording of other variables varied to a great extent. Overall, registries corresponded fairly well with the ICHOM set. Most registries proved to monitor and improve the quality of diabetes care using guidelines as a benchmark. The effects on national healthcare policy were more variable and often less clear.

CONCLUSIONS

National diabetes registries confer clear insights into diagnostics, complications, and treatment. The extent to which registries influenced national healthcare policy was less clear. A globally implemented standard outcome set has the potential to improve concordance between national registries, enhance the comparison and exchange of diabetes outcomes, and allocate resources and interventions where most needed.

Factors associated with glycaemic control in adults with Type 1 diabetes: a registry-based analysis including 7601 individuals from 34 centres in Norway

AIMS

To use data from the Norwegian Diabetes Registry for Adults and Statistics Norway to assess factors associated with glycaemic control in type 1 diabetes.

METHODS

The analyses included all individuals aged ≥18 years who had a type 1 diabetes duration of >2 years and a recorded value in the registry between 2013 and 2015 (n=7601). Predicted mean HbA_1c levels for subgroups of participants were assessed using linear regression analysis.

RESULTS

Young age (18-25 years), low education levels, smoking, living alone, exercising infrequently, monitoring glucose infrequently, high insulin requirements, low frequency of symptomatic hypoglycaemia, history of ketoacidosis and a BMI <18.5 kg/m² were associated with a 2-12-mmol/mol (0.2-1.1%) higher HbA_1c level. Those with 10-15 years of diabetes duration had 5-mmol/mol (0.5%) higher HbA_1c level than those who had a diabetes duration of 2-5 years. Sex, participation (ever) in a diabetes education course, or ever experiencing serious hypoglycaemia were not associated with glycaemic control.

CONCLUSIONS

We present representative national data on factors that were associated with glycaemic control. A better understanding and awareness of these factors, together with technological advances in diabetes management, could lead to more personalized management strategies, better glycaemic control and a lower risk of diabetes complications.