The relationship between HbA1c level, symptoms and self-rated health in type 2 diabetic patients

Objective

Improving glycaemic control is generally supposed to reduce symptoms experienced by type 2 diabetic patients, but the relationships between glycated haemoglobin (HbA_1c), diabetes-related symptoms, and self-rated health (SRH) are unclarified. This study explored the relationships between these aspects of diabetes control.

Design

A cross-sectional study one year after diagnosis of type 2 diabetes.

Subjects

A population-based sample of 606 type 2 diabetic patients, median age 65.6 years at diagnosis, regularly reviewed in primary care.

Main outcome measures

The relationships between HbA_1c, diabetes-related symptoms, and SRH.

Results

The patients’ median HbA_1c was 7.8 (reference interval: 5.4–7.4 % at the time of the study). 270 (45.2%) reported diabetes-related symptoms within the past 14 days. SRH was associated with symptom score (γ = 0.30, p < 0.001) and HbA_1c (γ = 0.17, p = 0.038) after correction for covariates. The relation between HbA_1c and symptom score was explained by SRH together with other confounders, e.g. hypertension (γ = 0.02, p = 0.40). The relation between the symptom fatigue and SRH was not explained by symptom score and significantly modified the direct association between symptom score and SRH.

Conclusions

Symptom relief may not occur even when HbA_1c level is at its lowest average level in the natural history of diabetes, and symptoms and SRH are closely linked. Monitoring symptoms in the clinical encounter to extend information on disease severity, as measured e.g. by HbA_1c, may help general practitioners and patients to understand the possible impact of treatments and of disease manifestations in order to obtain optimum disease control.Key Words: Family practice, glycosylated haemoglobin A, health status, signs and symptoms, type 2 diabetes mellitusTo reduce complications, lowering of HbA1c is a primary objective in diabetes care.

• Many patients experience diabetes-related symptoms in spite of acceptable glycaemic control.
• These symptoms are closely related to poor SRH while the association with HbA_1c is weak.

Patients with type 2 diabetes mellitus (T2DM) are commonly treated in general practice where treatment typically aims to improve glycaemic control in order to prevent complications [1], reduce symptom burden, and improve perceived health [2]. Moreover, the experience of obtaining these goals may improve patients’ motivation for treatment adherence, e.g. lifestyle changes and medication [3,4].Poor glycaemic control is related to symptoms such as frequent urination, genital itching, and unintended weight loss [5,6]. The association between glycated haemoglobin (HbA_1c) levels and specific symptoms is not necessarily close [7,8] except among dysregulated patients, e.g. at the time of diagnosis [5] or in patients with longstanding diabetes [2,6]. Despite the central role of symptom amelioration in treatment, few studies have looked into the relation between HbA_1c level and symptoms when HbA_1c is supposed to be at its lowest average level in the natural history of diabetes [7,9].General practitioners (GPs) and patients may evaluate the patient''s health differently [10]. The association between the patient''s HbA_1c level and perceived health is weak [2], or non-existent [1,11]. The patients’ perceived health gauged by a single question, known as perceived health, self-assessed health, or self-rated health (SRH), has been shown to vary with other factors than HbA_1c such as symptoms [12,13], sociodemographic factors [14], comorbidities [14–16], and functional ability [12,14]. Recent research has shown that SRH predicts which patients have a higher risk of diabetic complications even after accounting for established risk factors such as HbA_1c, but this predictive value may be mediated by presence of symptoms which were not accounted for [16]. Yet the relationships between HbA_1c and symptoms, both of which are important treatment targets, and SRH, which is a motivational factor for treatment adherence [2,3], are unclarified. A better insight into these relationships may help GPs to tailor treatments such as to maintain or improve patients’ health, which may include motivating the patient for treatment adherence.In a population-based sample of patients with T2DM seen in general practice one year after diabetes diagnosis we examined the relationships between HbA_1c, symptoms, and SRH primarily to see whether high HbA_1c levels are associated with many symptoms and low SRH ratings, and whether many symptoms are associated with low SRH ratings.