Occurrence and quality of anticoagulant treatment of chronic atrial fibrillation in primary health care in Sweden: a retrospective study on electronic patient records

BACKGROUND: Chronic atrial fibrillation is a prevalent cardiac disorder. The literature indicates varying proportions of those treated with anticoagulants, and varying intensity of anticoagulation. Electronic patient records are providing us with clinical data concerning management of anticoagulant treatment in real-life practice that is useful for audits. We aimed to assess warfarin treatment for chronic atrial fibrillation in primary health care with regard to prevalence, incidence, the proportion treated and the quality of anticoagulation control. METHODS: Five primary health care centres in Stockholm with a registered population of 75146 participated in a one-year retrospective study of electronic patient records up until May 2000. All patients over 18 years of age with an encounter labelled 'Atrial fibrillation' were identified, and all records of patients on warfarin treatment were manually reviewed. Main outcome measures were number of patients with chronic atrial fibrillation, number of patients on wafarin treatment, and time within the therapeutic prothrombin range. RESULTS: In total, 419 patients had chronic atrial fibrillation, giving a prevalence of 0.60% (age-adjusted 0.62%), the age group 65 years or older accounted for 91.6%, and 50.1% were women. Out of these, 50.4% (211 patients) were established on warfarin treatment for chronic atrial fibrillation (0.28% of the population), and there was a predominance of men (p = 0.02). Fifty-four patients started treatment with warfarin for chronic atrial fibrillation (0.07% of the population). Among 25 randomly selected patients on established treatment, the proportion of time within the therapeutic range was 70.2%. Among 24 randomly selected patients starting treatment, the proportion of time with therapeutic values was 54.2% and 66.9% the first and second months of treatment, respectively. CONCLUSIONS: Chronic atrial fibrillation is common among the elderly in primary health care, and about half of these patients are treated with warfarin. It appears to be under-diagnosed, and may also be under-treated. About two thirds of treatment time is spent within the therapeutic range, and further improvement of the quality of anticoagulation control with warfarin may therefore be hard to achieve

Anticoagulant treatment in primary health care in Sweden – prevalence, incidence and treatment diagnosis: a retrospective study on electronic patient records in a registered population

BACKGROUND: The indications for warfarin treatment in primary health care are increasing. An undertreatment with warfarin is reported in the prevention of embolic stroke in patients with chronic atrial fibrillation, and can be suspected for other indications. Information on the prevalence and incidence of diseases treated with warfarin would reveal useful data for audits concerning management of anticoagulant treatment. We aimed to assess warfarin treatment in primary health care with regard to prevalence, incidence, treatment diagnosis and patient characteristics. METHODS: A one-year retrospective study of electronic patient records up to May 2000 in primary health care in Stockholm, Sweden. Five primary health care centres with a registered population of 75 146. Main outcome measures were prevalence, incidence and treatment diagnosis. RESULTS: Five hundred and seven patients, mean age 71.9 years, were on warfarin treatment. The prevalence was 0.67% (age-adjusted 0.75%), and it was significantly higher for men (0.78%) than for women (0.58%) (p = 0.01). In the age group 75–84 years the prevalence was 4.54%. The most prevalent treatment diagnosis was chronic atrial fibrillation (0.28%), which was more predominant for males (p = 0.02), followed by cerebrovascular disease (0.13%) and deep venous thrombosis (0.13%). The yearly incidence of warfarin treatment was 0.17%, with chronic atrial fibrillation as the predominant treatment diagnosis. CONCLUSION: Warfarin treatment in primary health care is prevalent among the elderly. Chronic atrial fibrillation is the main treatment diagnosis. There is a gender difference favouring men in general and chronic atrial fibrillation as the treatment diagnosis

Resource consumption and management associated with monitoring of warfarin treatment in primary health care in Sweden

BACKGROUND: Warfarin is used for the prevention and treatment of various thromboembolic complications. It is an efficacious anticoagulant, but it has a narrow therapeutic range, and regular monitoring is required to ensure therapeutic efficacy and at the same time avoid life-threatening adverse events. The objective was to assess management and resource consumption associated with patient monitoring episodes during warfarin treatment in primary health care in Sweden. METHODS: Delphi technique was used to systematically explore attitudes, demands and priorities, and to collect informed judgements related to monitoring of warfarin treatment. Two separate Delphi-panels were performed in three and two rounds, respectively, one concerning tests taken in primary health care centres, involving 34 GPs and 10 registered nurses, and one concerning tests taken in patients' homes, involving 49 district nurses. RESULTS: In the primary health care panel 10 of the 34 GPs regularly collaborated with a registered nurse. Average time for one monitoring episode was estimated to 10.1 minutes for a GP and 21.4 minutes for a nurse, when a nurse assisted a doctor. The average time for monitoring was 17.6 minutes for a GP when not assisted by a nurse. Considering all the monitoring episodes, 11.6% of patient blood samples were taken in the individual patient's home. Average time for such a monitoring episode was estimated to 88.2 minutes. Of all the visits, 8.2% were performed in vain and took on average 44.6 minutes. In both studies, approximately 20 different elements of work concerning management of patients during warfarin treatment were identified. CONCLUSION: Monitoring of patients during treatment with warfarin in primary health care in Sweden involves many elements of work, and demands large resources, especially when tests are taken in the patient's home

Validity of resource-use data in economic evaluations

Aims: To analyse issues associated with resource-use data collection in economic evaluations, aiming at improvement in the design and conduct of future studies.Methods: Paper I: A health-economic study in the Swedish sub-set of patients in the Heart Outcomes Prevention Evaluation (HOPE) trial. The objective was to assess if ramipril, an angiotensin-converting-enzyme inhibitor, was cost-effective as compared to placebo. HOPE was a clinical multinational study (n=9 297) in patients at high risk of a cardiovascular event. Primary end-point was a composite of cardiovascular events. Paper II: A cost-effectiveness analysis of two alternative programmes for the eradication of EMRSA-16 based on decision analytical modelling. The background was an outbreak of EMRSA-16, which from a single patient assumed epidemic proportions despite preventive actions. Paper III: A cost-analysis of laparoscopic (LR) versus open resection (OR) of colon cancer after 12 weeks in a Swedish sub-set of patients in the Colon Cancer Laparoscopic or Open Resection (COLOR) study. Paper IV: Design of a new health-economic study based on COLOR II, a study comparing laparoscopic and open surgery for rectal cancer. Experience gained in previous studies was used to improve the principles for the design of the study.Results: Paper 1: The cost/life year gained was 1 940. Paper II: The forceful eradication programme was found to be cost-saving shortly after 2 years of implementation. Modelling is a suitable method in complex situations with scarce information. Paper III: From the perspective of the health care system costs were significantly higher in the LR group (mean difference 2 244, p=0.018). Societal costs did not differ significantly between the groups (mean difference 1 846). The analyses of paper I and III were associated with methodological problems. Paper IV: It was possible to increase the power and to avoid other methodological problems previously encountered by designing the study differently.Conclusions: Health-economic evaluations alongside clinical trials are associated with numerous methodological issues. The framing of the research question and the design of the study have a great influence on the validity of the result, and thus the basis for health-care decisions