Mean Prevalence Of Anaemia Research Articles

Epidemiology of anemia

Worldwide, the prevalence of anemia is high, and iron deficiency anemia is the fifth most common disorder according to the study called "Global burden of disease". It can be attributed to a number of factors, complex pathomechanisms, and etiology is highly variable in terms of age, gender, and geographical distribution. The prevalence of anemia increases with age. Demographic change and the aging of the population are now faster than in previous decades, posing major challenges to societies and health systems. The mean prevalence of anemia in the elderly is 17%, but significantly higher among nursing-home (47%) and hospitalized elderly (40%). The cause is usually multifactorial and often, due to comorbidities, several mechanisms are involved at the same time. The prevalence of preoperative anemia was higher (35%) than the prevalence of anemia in the general population, and evidence showed an unfavorable effect on postoperative morbidity and mortality. Timely identification and correction is a multidisciplinary task and a shared responsibility for both Patient Blood Management program and improving the patients' life expectancy. Orv Hetil. 2020; 161(37): 1569-1573.

On the role of iron therapy for reducing allogeneic blood transfusion in orthopaedic surgery.

The prevalence of pre-operative anaemia may be high among surgical patients, depending on the patients’ co-morbidities, gender, age and the underlying pathology for which they require surgery. In this regard, a recent systematic review showed that the weighted mean prevalence of anaemia was 24% in patients undergoing elective knee or hip surgery and 45% in those undergoing surgery because of a hip fracture1. In addition, it is worth noting that the proportion of older patients who undergo major orthopaedic surgery is rising progressively, and a high prevalence of anaemia (43%) was observed in a retrospective cohort of 57,636 veterans aged 65 years or older who underwent major elective and non-elective orthopaedic surgery2. Iron deficiency and chronic inflammation (including mild to moderate renal failure), with or without iron deficiency, are the most common causes of pre-operative anaemia, although deficiencies of iron, folic acid and/or vitamin B12 without anaemia are also frequent, especially among an elderly population. Saleh et al.3 reported that 19.6% (210/1,142) of admissions for elective total knee or hip replacement were anaemic compared with local population reference ranges (males 13 g/dL; females, 11.5 g/dL), with 76 of these anaemic patients having a haemoglobin (Hb) <11 g/dL and 13 having a Hb <10 g/dL. Regarding the types of anaemia, 135 had normocytic normochromic anaemia, 49 showed hypochromic varieties of anaemia, and 26 were classified as having other types of anaemia. Similarly, in another series of 715 patients undergoing major elective orthopaedic surgery the prevalence of pre-operative anaemia was 10.5%, because of haematinic deficiency (31%), chronic inflammation with or without iron deficiency (31%), and mixed or unknown cause (38%)4. Interestingly, iron deficiency was present in 18% of non-anaemic patients, vitamin B12 deficiency in 5%, and folate deficiency in 2%4. These deficiencies might blunt the response to erythropoiesis-stimulating agents, and delay the recovery from post-operative anaemia. In addition, almost 20% of patients had a Hb level <13 g/dL4 and it is well known that a low pre-operative Hb level is one of the major predictive factors for requiring peri-operative blood transfusion in orthopaedic surgery with moderate to high peri-operative blood loss5–7. In this regard, a European study including almost 4,000 patients showed an inverse relationship between pre-operative Hb values and the probability of receiving allogeneic blood transfusion (e.g., 10–18% for Hb 15 g/dL, 20–30% for Hb 13 g/dL, 50–60% for Hb 10 g/dL; 70–75% for Hb 8 g/dL)8. Similarly, 30 to 70% of patients undergoing hip fracture repair received allogeneic blood transfusion peri-operatively, and the logistic regression analysis identified pre-operative Hb value as an independent predictor of the need for these transfusions9. The limited physiological reserve and the higher prevalence of unrecognised cardiovascular disease may render the elderly population vulnerable to milder degrees of anaemia when undergoing the stress of surgery. In this regard, two large retrospective cohort studies of patients who underwent major non-cardiac surgery found that the adjusted risk of 30-day post-operative mortality and cardiac morbidity begins to rise when pre-operative haematocrit levels decrease to less than 39%2,10. On the other hand, major orthopaedic procedures are associated with a significant peri-operative blood loss. As a consequence, up to 90% of patients undergoing such procedures develop post-operative anaemia, which may be aggravated by inflammation-induced blunted erythropoiesis, especially through decreased iron availability (i.e, hepcidin-dependent down-regulation of intestinal absorption and impaired mobilisation from body stores)11. The correction of severe post-operative anaemia often requires allogeneic blood transfusion. Orthopaedic surgical patients at risk of developing severe post-operative anaemia and receiving peri-operative allogeneic blood transfusion should, therefore, be identified, on the basis of red blood cell mass (reflected by haemoglobin concentration on the day of pre-operative assessment), the lowest haemoglobin concentration that the patient can tolerate (transfusion trigger), and the expected blood loss (e.g., using Mercuriali’s algorithm)12. Whenever clinically feasible, these patients should have their Hb level and iron status (serum iron, ferritin, and transferrin saturation index) tested preferably 30 days before the scheduled surgical procedure13. For patients older than 60 years, vitamin B12 and folic acid should also be measured13. Any deficiency should be corrected prior to surgery, and unexplained anaemia should always be considered as secondary to some other process and, therefore, elective surgery should be deferred until a diagnosis has been made13,14.

Anaemia is a major public health problem in Tanzania

In Tanzania health workers surveyed 10037 adults (=or> 15 years old) in rural villages in the Morogoro Rural District (a poor rural area) Kilimanjaro region of Hai District (the most wealthy rural area in the study) Mara region (a poor rural area) and in the urban areas of Manzese and Kimara in Dar es Salaam to determine the prevalence of anemia in adults. The prevalence of anemia in males (hemoglobin [Hb] < 13 g/dl) and in females (Hb < 12 g/dl) varied from 29.8% in Kilimanjaro to 79.9% in Mara and 25.8% in Kilimanjaro to 80.5% in Morogoro respectively. Anemia was always more prevalent in Morogoro and Mara than in Kilimanjaro or Dar es Salaam. When the researchers used Hb levels of less than 11 g/dl for males and less than 10 g/dl prevalence ranged from 3.1% in Kilimanjaro to 26.3% in Morogoro for men and 2.1% in Kilimanjaro to 26.8% in Morogoro for women. Mean Hb levels were 13.2 g/dl in Kilimanjaro 11.9 g/dl in Dar es Salaam 11.1 g/dl in Morogoro and 11.1 g/dl in Mara. The 5537 nonpregnant women had a consistently higher mean Hb level than did the 257 pregnant women (11.7 g/dl vs. 10 g/dl). Men in the older age groups had a higher prevalence of anemia in all areas except Mara than did younger men especially 65-year-old and older men. Age was not a factor in women however. Mean prevalence of anemia in males and females in the poorer rural areas was much higher than mean prevalence of anemia in males and females in other East African countries. Since anemia reduces maximum oxygen transport the high levels of anemia in Tanzania may impede work performance. Further anemia contributes to poor health also reducing work performance. These findings show that anemia is a major public health problem in Tanzania.