Health-related quality of life (HRQL)
HRQL refers to patients’ subjective accounts of functioning and/or overall well-being in relation to health status, and encompasses emotional and physical functioning. While clinical medicine usually gauges the severity of illness and success/failure of treatment via strictly objective criteria, HRQL measures are assessed directly from patient reports. Increasingly, the concept that patient perceptions of illness and/or wellness do not necessarily correlate with objective measures of morbidity is becoming accepted. Also, HRQL has critical implications, both for the individual and, when the person is unable to perform his/her daily functions, for society. Measures of function and well-being have been shown to predict both health-care expenditures and mortality. Lastly, HRQL data can provide physicians with vital information on the efficacy of any given treatment regimen.
Measurement of HRQL
Work exploring HRQL has exploded in scope and interest over the past decade. Two approaches to assessing HRQL in medical illness have emerged: global and disease-specific. Global HRQL measures assess daily functioning and emotional well-being without reference to specific disease symptoms (e.g. impact of illness upon communication skills). Disease-specific HRQL measures assess the impact of very specific symptoms or problems upon functioning or well-being, e.g. level of social embarrassment due to having a colostomy. No gold standard exists in terms of assessing HRQL in gastrointestinal disease and researchers disagree on the best approach.
In terms of type of HRQL instruments and diabetes, Jacobson and colleagues compared global vs. disease-specific measures in patients with type 2 diabetes. These researchers concluded that, when examining the impact of acute complications and/or regimens on HRQL, a disease-specific measure was most appropriate. A global measure (Medical Outcomes Study Short Form or MOS SF-36) was deemed most useful for examining relationships between patients’ experience of living with diabetes and other chronic diseases. Likewise, Anderson et al. found that, in a sample of 255 type 2 diabetic patients, exploring ‘within-disease’ parameters was best assessed via a disease-specific instrument, while relationships ‘between’ patient experiences of living with diabetes and HRQL and other diseases were best captured via global measures.
Several studies examining the impact of HRQL upon patients with upper gastrointestinal distress (typically dyspepsia) have utilised global measures, usually the SF-36 or some variant of that scale. Similarly, a larger-scale study investigated HRQL in patients with upper gastrointestinal symptoms from seven European countries, USA, Canada and Japan. This work concluded that, of the 5581 respondents (27% of whom also were diagnosed with diabetes, hypertension or asthma), the presence of gastrointestinal symptoms was associated with impaired well-being and daily life, as measured via the Psychological General Well-being Index (PGWB) and Interference with Daily Life Index (IDLI). Subjects with upper gastrointestinal symptoms (particularly ulcerlike symptoms) manifested poorer scores on these HRQL measures.
Others have opted to use batteries of assessment, encompassing both global and disease-specific measures. For example, Talley et al. applied a battery of validated measures, which included a short form of the Medical Outcomes Survey (SF-12), a Brief Symptom Inventory and gastrointestinal symptoms. The authors found that patients with functional dyspepsia had poorer mental health, social functioning and health perception, compared with patients with other conditions who presented for upper endoscopy.
Disease-specific measures in gastrointestinal diseases have been developed for several disease entities, including inflammatory bowel disease, IBS, gastro-oesophageal reflux disease (GORD), faecal incontinence and functional dyspepsia, with varying degrees of psychometric validation. However, no disease-specific quality of life measure exists for gastrointestinal dysfunction in diabetes.