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ABSTRACT: We evaluated peripheral blood tests to diagnose iron deficiency on medical wards in Blantyre, Malawi, where infection and HIV are prevalent. We compared full blood count, ferritin and serum transferrin receptor (TfR) levels with an estimation of iron in bone marrow aspirates. Of consecutive adults admitted with severe anaemia (haemoglobin <7 g/dl), 81 had satisfactory bone marrow aspirates. The main outcome measures were the validity of each test (sensitivity, specificity, and positive and negative predictive values) and likelihood ratios (LR) for iron deficiency. Twenty patients (25%) were iron deficient and 64 (79%) were HIV-positive. Iron deficiency was more common in HIV-negative compared with HIV-positive patients (59% vs. 16%; P<0.001). In HIV-positive patients, the optimal ferritin cut-off was 150 microg/l (sensitivity 20%, specificity 93%, LR 2.7), but no test was accurate enough to be clinically useful. In HIV-negative patients, ferritin was the single most accurate test (cut-off <70 microg/l, 100% specificity, 90% sensitive, LR if positive infinity, LR if negative 10). TfR measurement did not improve the accuracy. Mean cell volume was not a good predictor of iron status except in HIV-negative patients (cut-off <85 fl, specificity 71%, sensitivity 90%). In populations with high levels of infection and HIV, an HIV test is necessary to interpret any tests of iron deficiency. In HIV-negative patients, ferritin is the best blood test for iron deficiency, using a higher cut-off than usual. For HIV-positive patients, it is difficult to diagnose iron deficiency without bone marrow aspirates.
Transactions of the Royal Society of Tropical Medicine and Hygiene 06/2007; 101(6):613-7. · 2.16 Impact Factor
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ABSTRACT: Severe anaemia is a common presentation in non-pregnant adults admitted to hospital in southern Africa. Standard syndromic treatment based on data from the pre-HIV era is for iron deficiency, worms and malaria. We prospectively investigated 105 adults admitted consecutively to medical wards with haemoglobin < 7 g/dl. Those with acute blood loss were excluded. Patients were investigated for possible parasitic, bacterial, mycobacterial and nutritional causes of anaemia, including bone marrow aspiration, to identify potentially treatable causes. Seventy-nine per cent of patients were HIV-positive. One-third of patients had tuberculosis, which was diagnosed only by bone marrow culture in 8% of HIV-positive patients. In 21% of individuals bacteria were cultured, with non-typhi salmonella predominating and Streptococcus pneumoniae rare. Iron deficiency, hookworm infection and malaria were not common in HIV-positive anaemic adults, although heavy hookworm infections were found in 6 (27%) of the 22 HIV-negative anaemic adults. In conclusion, conventional treatment for severe anaemia in adults is not appropriate in an area of high HIV prevalence. Occult mycobacterial disease and bacteraemia are common, but iron deficiency is not common in HIV-positive patients. In addition to iron supplements, management of severe anaemia should include investigation for tuberculosis, and consideration of antibiotics active against enterobacteria.
Transactions of the Royal Society of Tropical Medicine and Hygiene 09/2005; 99(8):561-7. · 2.16 Impact Factor
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ABSTRACT: This paper estimates the degree and nature of imperfections in the timber markets for the South Pacific Region of Colombia. These markets are described under the structure/conduct/performance paradigm. An econometric analysis was undertaken to estimate the degree of imperfection. Market structures indicate high levels of seller concentration. These are result of barriers to entry associated with: knowledge and capital requirements; deficiencies in the banking system; vertical integration of participants;available transportation; and other institutional constraints. These imperfections create inequalities in the distribution of income, unemployment and regional poverty. As a consequence the timber industry's contribution to socioeconomic progress is limited and produces a negative impact on the conservation of forestecosystems.
Lecturas de Economía. 02/2005;
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ABSTRACT: To determine the contribution of a blood culture service to the diagnosis of fever in a resource-poor setting and to identify clinical predictors of specific bloodstream infections (BSI).
In a descriptive, prospective study at the Medical Wards at Queen Elizabeth Central Hospital, Blantyre, Malawi, we tried to identify a specific cause of fever in febrile patients, comparing the use of routinely available diagnostic methods with the same methods plus blood culture. Clinical predictors of specific BSIs were sought.
A total of 352 patients admitted with fever (axillary temperature > or =37.4 degrees C) or a history of fever within the last 4 days were enrolled. Tuberculosis (TB) was the diagnosis most commonly suspected initially on clinical grounds (28%), followed by lower respiratory tract infection (16%), malaria (12%) and gastroenteritis (5%). Blood cultures were positive in 128 patients (36%); Mycobacterium tuberculosis was the most commonly isolated organism (57 patients). In most cases the diagnosis of TB had already been made using routinely available diagnostic methods, including chest radiography. In all 16 cases of Streptococcus pneumoniae bacteraemia, infection with this agent was clinically suspected, usually on the basis of pulmonary symptoms and signs. In contrast, in 30 of 65 patients (65%) with non-typhi salmonellae (NTS) bacteraemia, there were no symptoms or signs specifically suggestive of this diagnosis. Fever > or =39 degrees C and splenomegaly predicted NTS bacteraemia with an odds ratio of 8.4 (95% confidence interval 3.4-20.6, P < 0.001).
BSIs are common among patients admitted with fever. While BSI with mycobacteraemia and S. pneumoniae can usually be predicted on clinical grounds and with routinely available diagnostic methods, NTS bacteraemia often presents as a primary BSI without localizing symptoms and signs. Splenomegaly in this population indicates NTS bacteraemia rather than malaria.
Tropical Medicine & International Health 08/2004; 9(8):928-34. · 2.80 Impact Factor
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ABSTRACT: To explore the views of clinicians and lay people about the minimum benefit needed to justify drug treatment to prevent heart attacks, and to explore the rationale behind treatment decisions.
Qualitative study using semi-structured interviews.
4 general practitioners, 4 practice nurses, and 18 lay people.
8 general practices and 6 community settings across Liverpool.
Participants varied widely in the minimum acceptable benefits chosen. Most people found the concepts difficult initially, and few appreciated that increased length of treatment should increase absolute benefits. Lay people usually wanted to make decisions for themselves, and clinicians supported this. Participants wanted to consider adverse effects and costs of treatment. Dislike of drug taking was common, and many people preferred lifestyle change to an imperfect treatment. Quality of life and personal views were more important than an individual's age.
Evidence based guidelines make assumptions about people's preferences, and, by using 10 year estimates of risk, inflate the apparent benefits of treatment. It is unlikely that guidelines could incorporate the wide range of people's preferences, and true dialogue is necessary between clinicians and patients before starting long term preventive treatment.
BMJ (Clinical research ed.). 11/2003; 327(7419):841.
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ABSTRACT: Despite high seroprevalence there are few recent studies of the effect of human immunodeficiency virus (HIV) on hospitals in sub-Saharan Africa. We examined 1226 consecutive patients admitted to medical and surgical wards in Blantyre, Malawi during two 2-week periods in October 1999 and January 2000: 70% of medical patients were HIV-positive and 45% had acquired immune deficiency syndrome (AIDS); 36% of surgical patients were HIV-positive and 8% had AIDS. Seroprevalence rose to a peak among 30-40 year olds; 91% of medical, 56% of surgical and 80% of all patients in this age group were HIV-positive. Seropositive women were younger than seropositive men (median age 29 vs. 35 years, P < 0.0001). Symptoms strongly indicative of HIV were history of shingles, chronic diarrhoea or fever or cough, history of tuberculosis (TB), weight loss and persistent itchy rash (adjusted odds ratios [AORs] all > 5). Clinical signs strongly indicative of HIV were oral hairy leukoplakia, shingles scar, Kaposi's sarcoma, oral thrush and hair loss (AORs all > 10). Of surgical patients with 'deep infections' (breast abscess, pyomyositis, osteomyelitis, septic arthritis and multiple abscesses), 52% were HIV-positive (OR compared with other surgical patients = 2.4). Severe bacterial infections, TB and AIDS caused 68% of deaths. HIV dominates adult medicine, is a major part of adult surgery, is the main cause of death in hospital and affects the economically active age group of the population.
Transactions of the Royal Society of Tropical Medicine and Hygiene 97(1):91-6. · 2.16 Impact Factor
