Testa and Simonson, attempting to overcome the uncontrolled nature of earlier studies, conducted a randomised, controlled, double-blind study of the short-term impact of glycaemic control upon HRQL in patients with type 2 diabetes.
They concluded that treatment, and subsequent good glycaemic controls was associated with improved HRQL (measured using a visual analogue scale) and a number of health economic indices related to work (e.g. less absenteeism, greater work productivity, fewer bed days and fewer restricted activity days).
Additionally, these researchers concluded that the rate of HRQL deterioration due to increasing symptoms was progressive with worsening glycaemic control, suggesting, on the other hand, that improvement of glycaemic control also might facilitate the improvement of the HRQL.
Prokinetic therapy in diabetes and quality of life Studies assessing prokinetic therapy for gastrointestinal symptoms and HRQL in both diabetic patients and those with alternative aetiologies have proliferated over the last decade. A number of these studies have assessed HRQL in addition to traditional symptom improvement indices.
Cutts et al. found that one year of treatment with prokinetic therapy (cisapride or domperidone) resulted in improved HRQL as measured by the Sickness Impact Profile (SIP), as well as symptom improvement in a group of patients with severe dyspeptic symptoms of both diabetic and idiopathic aetiologies. Soykan et al. followed 146 patients with ‘gastroparesis’ symptoms and delayed gastric emptying, treated with prokinetic therapy and other treatment modalities for six years after initial diagnosis. They assessed psychological and HRQL (by visual analogue scale) parameters, as well as gastric emptying and gastrointestinal symptoms, and found that 74% responded favourably to prokinetic therapy.
Also, those patients with a presumed viral aetiology had greater symptom resolution and improved HRQL, as compared to their idiopathic counterparts. The same group of researchers investigated the use of oral domperidone in the treatment of 17 patients with a documented delay in gastric emptying. They found that domperidone therapy (average 23.3 months) significantly reduced nausea, vomiting, abdominal pain and bloating and resulted in enhanced HRQL (measured via select questions from the SF-36) in 88% of the patients treated, with minimal side effects (three patients developed gynaecomastia). Of the 15 patients re-evaluated at follow-up, gastric emptying of a solid meal was significantly accelerated to a normal rate. However, none of the studies cited above compared their samples to matched controls, and Cutts et al. did not document delayed gastric emptying.
Rashed et al. examined autonomic functioning as a determinant of quality of life improvement in a group of seven patients with diabetic gastroparesis, in an uncontrolled study. These investigators compared patients in an open label trial of domperidone for 12 months, assessing gastrointestinal symptoms via the Total Symptom Score (TSS), a summed index gathered from patient reports, HRQL via the SIP and autonomic functioning, reported as the total autonomic score (TAS), previously described. Patients showed a significant improvement of 56% in the total symptom score at baseline vs. 12 months. SIP scores improved in six of seven patients, with a median improvement level of 22%, from baseline to one year. Autonomic functioning status at baseline correlated significantly with the SIP Psychosocial Dimension scale (measuring emotional behaviour, communication, social interaction, and alertness behaviour). Hence, in the small sample of diabetic gastroparesis patients, domperidone use was associated with improvement in both gastrointestinal symptoms and HRQL.
However, in patients with impaired autonomic functioning, the level of HRQL manifested less improvement. These findings may have implications for selection of diabetic patient subgroups that may benefit from prokinetic therapy.
These data were substantiated in the recent multi-centre examination of the effect of treatment with domperidone on HRQOL in diabetic gastropathy. Silvers et al. and Farup et al. reported on use of domperidone therapy in a sample of patients with insulin-treated diabetes and symptoms of gastroparesis. These researchers conducted a four-week, double-blind, placebo-controlled study and found that patients who responded favourably to domperidone experienced significantly improved gastrointestinal symptom relief and HRQL (measured via the SF-36) compared to placebo.
In a long-term follow-up of idiopathic gastroparesis, 12 patients (all of whom had taken prokinetic drugs at some point) of presumed viral aetiology reported improved HRQL (measured via the SF-20), compared to the remainder with gastroparesis. These results suggest that prokinetic therapy is useful in the treatment of gastrointestinal symptoms in both diabetic and idiopathic subgroups of patients. Domperidone therapy may potentially be most efficacious in those diabetic patients with delayed gastric emptying who have preserved autonomic function.
In addition to prokinetic therapies and HRQL, gastric electrical stimulation is currently being investigated in multi-centre trials across the USA and internationally. Preliminary results indicate that, over a 24 month treatment of 28 patients with severe dyspepsia (primary symptoms of intractable nausea and vomiting), gastric pacing was associated with significant changes in sympathetic cholinergic function, decreased gastrointestinal symptoms and HRQL. Recent approval of this treatment modality of gastric pacing as a Humanitarian Use Device by the US Food and Drug Administration will allow further exploration of this treatment for patients who do not respond to, or cannot tolerate, available drug therapies.
In conclusion, measurement of health-related quality of life provides the physician with another tool with which to monitor a patient’s progress during long-term treatment for chronic disease, such as diabetes mellitus. This type of assessment also provides a vehicle for communication between physician and patient – a means for the physician to understand the phenomenological ‘experience’ of the disease and promote treatment. In diabetic patients with gastrointestinal symptoms, which can further complicate self-management and so easily lead to discouragement and frustration, this may prove to be one of the most valuable applications of HRQL information.