Methodological and results approaches
The four case histories in this study are representative of patients with conditions frequently seen in medical practice. Diseases of the gastrointestinal tract account for about 6% of all reported consultations in Sweden . Gastritis, dyspepsia, and unspecified diseases in the ventricle and duodenum (patients 1 and 2) are diagnosed in 1.6% of the population; oesophagitis and reflux (patient 3) in 0.9%; and different ulcers (patient 4) in 0.6%.
The clinicians who participated in this study were not representative of a randomised selection of clinicians in Sweden but rather of a select group with a special interest in patients with symptoms from the gastrointestinal tract. Since their experience with these patients was extensive, they should have been able to develop a treatment policy. One would expect a variation in treatment strategy in this group to be more limited than among a randomised selection of clinicians.
The results underpin existing evidence that variations in medical practice exist [14–16]. This study presents variations both in treatment strategy and in what information is considered important for making treatment decisions. The histories of patients with diffuse symptoms but no objective findings (patients 1 and 2) gave rise to more extensive variations than did the case histories of patients 3 and 4 where the symptoms were more obviously related to a diagnosis (patient 3) or where more obvious organic changes existed (patient 4). Uncertainty in diagnosis could lead to uncertainty regarding which outcome of alternative interventions is optimal [17, 18]. A meta-analysis that evaluates the most effective treatment in patients with functional dyspepsia  recommended the eradication of H. pylori if the treatment is to be effective from the patient's perspective, whereas other randomised, double-blind, controlled studies find that eradication has no beneficial effect . These results were underpinned by the variations observed in this study.
Uncertainty due to lack of knowledge or professional competence may lead to qualitative differences. In this study, different management strategies were recommended for patients with reflux disease (patient 3), for example, eradication treatment as one strategy and changes in life-style as another. However, evidence in the literature presenting eradication as an optimal management of reflux is lacking . Instead, this management strategy raises the cost to society and to the patient and causes unnecessary antibiotic pressure. Randomised, double-blinded, prospective studies conclude that the only indication for treating dyspepsia with proton pump inhibitors (PPIs) is the presence of an ulcer or reflux . However, the majority of clinicians prescribed PPIs and H2-receptor antagonists for the treatment of dyspepsia, although no evidence of an effect with this treatment compared to placebo has been documented [9, 10]. Thus, this regimen has led to high costs for society without any benefits. The drug costs for treatment of ventricular and duodenal ulcers and of reflux, including eradication treatment, were SEK 1.6 billion [USD 210 million] in 1998 in Sweden , while The Swedish Council on Technology Assessment in Health Care reports that society's direct and indirect costs for dyspepsia were between SEK 3.7 and 4.4 billion [USD 490 and 590 million] in 2000 .
From the informants' answers to the question "Which factors are most important to consider in your decision?", the completeness of some of the answers given in the interviews could be questioned. Most likely, the clinicians failed to answer the question in full as they left out many factors worthy of consideration. Other factors in the patient's life such as stress, mental mood, working situation, and diet were not mentioned by the clinicians in the interviews but should often be considered in treatment strategies in an actual clinical situation.
Within each of the three specialities, clinicians believed that their colleagues would treat patients in the same way as they themselves did. This aspect of "professional certainty" implies that clinicians believe that their practice is correct, irrespective of how much it in fact differs from that of other clinicians [18, 19]. This unawareness of variation in the management of frequently seen patients may indicate a lack of communication and discussion about everyday cases. Such discussions are perhaps reserved for more "complex" and rare cases.
Opportunities to change clinicians' practice
Among the causes of variation in medical practice, the influence of factors like patient characteristics (e.g. age, sex, morbidity, and personal preferences) could be more or less regarded as legitimate to explain variations in practice . Other factors, like resource capacity, could be influenced by, for example, budget restrictions while management policy and practice style are more resistant to change . These latter factors should therefore be the targets of efforts to change. However, many attempts to implement evidence by information alone, for example in the form of clinical practice guidelines, have failed to change management strategies [20–23]. Instead, a combination of methods is most likely needed if a permanent change is to occur . Furthermore, it is of utmost importance that potential barriers are identified and that the clinicians who will be affected support the clinical practice guidelines to be implemented.
In recent years, the individual autonomy of patients and letting patients' preferences influence the choice of intervention have been emphasised . In this study, such a strategy could explain why some clinicians mentioned that they felt pressured by patients to perform an intervention, even when the optimal strategy was non-intervention.