The accuracy of mean corpuscular volume guided anaemia classification in primary care.

BACKGROUND: Anemia can be categorized into micro-, normo- or macrocytic anemia based on the mean corpuscular volume (MCV). This categorization might help to define the etiology of anemia. METHODS: The cohort consisted of patients newly diagnosed with anaemia in primary care. Seven aetiologies of anaemia were defined, based on an extensive laboratory protocol. Two assumptions were tested: (i) MCV <80 fl (microcytic) excludes vitamin B12 deficiency, folic acid deficiency, suspected haemolysis and suspected bone marrow disease as anaemia aetiology. (ii) MCV >100 fl (macrocytic) excludes iron deficiency anaemia, anaemia of chronic disease and renal anaemia as anaemia aetiology. RESULTS: Data of 4129 patients were analysed. One anaemia aetiology could be assigned to 2422 (59%) patients, more than one anaemia aetiology to 888 (22%) patients and uncertainty regarding the aetiology remained in 819 (20%) patients. MCV values were within the normal range in 3505 patients (85%). In 59 of 365 microcytic patients (16%), the anaemia aetiology was not in accordance with the first assumption. In 233 of 259 macrocytic patients (90%), the anaemia aetiology was not in accordance with the second assumption. CONCLUSIONS: Anaemia aetiologies might be ruled out incorrectly if MCV guided classification is used as a first step in the diagnostic work-up of anaemia. We recommend using a broader set of laboratory tests, independent of MCV.

Preventing overuse of laboratory diagnostics: a case study into diagnosing anaemia in Dutch general practice.

BACKGROUND: More information is often thought to improve medical decision-making, which may lead to test overuse. This study assesses which out of 15 laboratory tests contribute to diagnosing the underlying cause of anaemia by general practitioners (GPs) and determines a potentially more efficient subset of tests for setting the correct diagnosis. METHODS: Logistic regression was performed to determine the impact of individual tests on the (correct) diagnosis. The statistically optimal test subset for diagnosing a (correct) underlying cause of anaemia by GPs was determined using data from a previous survey including cases of real-world anaemia patients. RESULTS: Only 9 (60%) of the laboratory tests, and patient age, contributed significantly to the GPs' ability to diagnose an underlying cause of anaemia (CRP, ESR, ferritin, folic acid, haemoglobin, leukocytes, eGFR/MDRD, reticulocytes and serum iron). Diagnosing the correct underlying cause may require just five (33%) tests (CRP, ferritin, folic acid, MCV and transferrin), and patient age. CONCLUSIONS: In diagnosing the underlying cause of anaemia a subset of five tests has most added value. The real-world impact of using only this subset should be further investigated. As illustrated in this case study, a statistical approach to assessing the added value of tests may reduce test overuse.

Long-term outcomes in patients newly diagnosed with iron deficiency anaemia in general practice: a retrospective cohort study.

OBJECTIVES: To describe all iron deficiency anaemia (IDA)-related causes during follow-up of patients newly diagnosed with IDA and to assess whether a delayed colorectal cancer (CRC) diagnosis influences survival. DESIGN AND SETTING: Retrospective cohort study of patients from general practices in the Dordrecht area, the Netherlands. PARTICIPANTS: Men and women aged ≥50 years with a new diagnosis of IDA (ie, no anaemia 2 years previously). METHOD: From February 2007 to February 2018, all relevant data were collected from the files of the referral hospital. Early IDA-related cause was defined as established within 18 weeks after IDA diagnosis. Cox proportional-hazards regression was used to analyse survival of patients with CRC diagnosis. RESULTS: 587 patients with IDA were included with a median follow-up of 4.6 years. Early and late IDA-related causes could be established in 32% and 8% of patients, respectively. Early and late CRC was found in 8% and 2% of patients, respectively, and were located mainly right sided. After adjustment for age, gender and TNM classification, mortality risk was lower in patients with IDA with early CRC diagnosis, but not significantly (HR 0.30, 95% CI 0.09 to 1.02). CONCLUSION: Even with extended follow-up, the cause of IDA remains elusive in the majority of patients with IDA in general practice. However, patients with IDA are at increased risk for in particular right-sided CRC and a late diagnosis of CRC appears to have a detrimental effect on survival in patients with IDA.

Diagnostics in anaemia of chronic disease in general practice: a real-world retrospective cohort study.

BACKGROUND: Limited research has been performed that focused on the diagnosis of the underlying cause of anaemia of chronic disease (ACD) in general practice or on prevalence data of the underlying causes of ACD in general practice, although this is one of the most common types of anaemia. AIM: To clarify the diagnostic strategies of GPs in patients newly diagnosed with ACD and to determine the most common underlying causes. DESIGN & SETTING: Retrospective cohort study. METHOD: Patients newly diagnosed with ACD were selected based on laboratory criteria. ACD was defined as confirmed anaemia and ferritin levels above 100 µg/l combined with decreased iron and/or reduced transferrin. Additional medical information on patients was obtained from the electronic medical files of the GP and/or the referral hospital. RESULTS: Of the 267 analysed patients with ACD, additional investigations were performed in 205 patients (77%); in 31 patients (12%) the cause was apparent at the time of diagnosis, and for 31 patients (12%) no additional investigations were requested. In 210 (79%) of the 267 patients, an underlying cause was established, with infection (n = 68, 32%), autoimmune disease (n = 51, 24%) and malignancy (n = 48, 23%) as the most frequently observed etiologies. In 35 (13%) of the ACD patients, oral iron supplementation was prescribed by the GP. This was mainly done in patients with severe anaemia or less enhanced ferritin levels. CONCLUSION: For most patients with newly diagnosed ACD, the GP undertakes additional investigations to establish underlying causes. However, the cause of ACD remains unknown in a small proportion of patients. The use of oral iron supplementation in these patients requires caution.

Assessing the cost-effectiveness of a routine versus an extensive laboratory work-up in the diagnosis of anaemia in Dutch general practice.

Background Establishing the underlying cause of anaemia in general practice is a diagnostic challenge. Currently, general practitioners individually determine which laboratory tests to request (routine work-up) in order to diagnose the underlying cause. However, an extensive work-up (consisting of 14 tests) increases the proportion of patients correctly diagnosed. This study investigates the cost-effectiveness of this extensive work-up. Methods A decision-analytic model was developed, incorporating all societal costs from the moment a patient presents to a general practitioner with symptoms suggestive of anaemia (aged ≥ 50 years), until the patient was (correctly) diagnosed and treated in primary care, or referred to (and diagnosed in) secondary care. Model inputs were derived from an online survey among general practitioners, expert estimates and published data. The primary outcome measure was expressed as incremental cost per additional patient diagnosed with the correct underlying cause of anaemia in either work-up. Results The probability of general practitioners diagnosing the correct underlying cause increased from 49.6% (95% CI: 44.8% to 54.5%) in the routine work-up to 56.0% (95% CI: 51.2% to 60.8%) in the extensive work-up (i.e. +6.4% [95% CI: -0.6% to 13.1%]). Costs are expected to increase slightly from €842/patient (95% CI: €704 to €994) to €845/patient (95% CI: €711 to €994), i.e. +€3/patient (95% CI: €-35 to €40) in the extensive work-up, indicating incremental costs of €43 per additional patient correctly diagnosed. Conclusions The extensive laboratory work-up is more effective for diagnosing the underlying cause of anaemia by general practitioners, at a minimal increase in costs. As accompanying benefits in terms of quality of life and reduced productivity losses could not be captured in this analysis, the extensive work-up is likely cost-effective.

The effectiveness of a routine versus an extensive laboratory analysis in the diagnosis of anaemia in general practice.

Background We investigated the percentage of patients diagnosed with the correct underlying cause of anaemia by general practitioners when using an extensive versus a routine laboratory work-up. Methods An online survey was distributed among 836 general practitioners. The survey consisted of six cases, selected from an existing cohort of anaemia patients ( n = 3325). In three cases, general practitioners were asked to select the laboratory tests for further diagnostic examination from a list of 14 parameters (i.e. routine work-up). In the other three cases, general practitioners were presented with all 14 laboratory test results available (i.e. extensive work-up). General practitioners were asked to determine the underlying cause of anaemia in all six cases based on the test results, and these answers were compared with the answers of an expert panel. Results A total of 139 general practitioners (partly) responded to the survey (17%). The general practitioners were able to determine the underlying cause of anaemia in 53% of cases based on the routine work-up, whereas 62% of cases could be diagnosed using an extensive work-up ( P = 0.007). In addition, the probability of a correct diagnosis decreased with the patient's age and was also affected by the underlying cause itself, with anaemia of chronic disease being hardest to diagnose ( P = 0.003). Conclusion The use of an extensive laboratory work-up in patients with newly diagnosed anaemia is expected to increase the percentage of correct underlying causes established by general practitioners. Since the underlying cause can still not be established in 31.3% of anaemia patients, further research is necessary.