Pulmonary function test in transfusion-dependent beta-thalassemia patients

Race-neutral equations for assessment of lung function in children with thalassemia

The aim of this study was to assess pulmonary dysfunction in children with transfusion-dependent thalassemia (TDT) using the Global Lung Function Initiative (GLI) 2022 race-neutral spirometric reference equations and to determine the main predicting factors. The spirometric results of 68 children with TDT were compared to the results of 68 healthy control subjects using both GLI-2012 reference equations for Caucasians and GLI-2022 global equations. Associations between the spirometric data and various anthropometric, clinical, and laboratory parameters were analyzed to detect predictors of pulmonary dysfunction in this group of patients. Children with TDT showed significantly lower values of FVC and FEV1 with a predominance of the restrictive pattern (23.53%). Thalassemic children with the restrictive pattern were significantly older, had a longer duration of regular blood transfusion, lower height, weight, and BMI z-scores, higher average serum ferritin, and higher frequency of having a serum ferritin level >2500 ng/mL. The strongest predictor for having a restrictive spirometric pattern was high serum ferritin. Our analysis shows that the transition from GLI-2012 spirometric reference equations for Caucasians to the GLI-2022 global equations has led to a reduction in the prevalence rate of restrictive pulmonary dysfunction in children with TDT, which should not affect the patient outcome in the long term. Asymptomatic children with TDT exhibited a restrictive spirometric pattern in a significant proportion. The most important predictor was high serum ferritin. We encourage the inclusion of pulmonary function testing in the routine monitoring of patients with TDT, especially in older patients and those with iron overload.

Pulmonary function in patients with transfusion-dependent thalassemia and its associations with iron overload

In patients with transfusion-dependent thalassemia (TDT), pulmonary function impairment has been reported but data are conflicting. Moreover, it remains unclear whether pulmonary dysfunction is associated with iron overload. This study aimed to evaluate the pulmonary function in patients with TDT and to investigate the associations between pulmonary dysfunction and iron overload. It was a retrospective observational study. 101 patients with TDT were recruited for lung function tests. The most recent ferritin levels (pmol/L) and the magnetic resonance imaging (MRI) measurements of the myocardial and liver iron status, as measured by heart and liver T2* relaxation time (millisecond, ms) respectively, were retrieved from the computerized medical records. Only data within 12 months from the lung function measurement were included in the analysis. The serum ferritin, and the cardiac and liver T2* relaxation time were the surrogate indexes of body iron content. The threshold of abnormality in lung function was defined as under 80% of the predicted value. 101 subjects were recruited with a mean age of 25.1 years (standard deviation (SD) 7.9 years). Thirty-eight (38%) and five (5%) demonstrated restrictive and obstructive lung function deficits, respectively. A weak correlation of FVC %Predicted and TLC %Predicted with MRI myocardial T2* relaxation time (rho = 0.32, p = 0.03 and rho = 0.33, p = 0.03 respectively) was observed. By logistic regression, MRI cardiac T2* relaxation time was negatively associated with restrictive lung function deficit (B - 0.06; SE 0.03; Odds ratio 0.94; 95% confidence interval (CI) 0.89-0.99; p = 0.023) after adjusting for age, sex and body mass index. Restrictive pulmonary function deficit was commonly observed in patients with TDT, and the severity potentially correlates with myocardial iron content. Monitoring of lung function in this group of patients, particularly for those with iron overload, is important.

Pulmonary functions in Egyptian children with transfusion-dependent β-thalassemia

BACKGROUND

In β-thalassemia, there are varying degrees of ineffective haematopoiesis, intermittent haemolysis and iron overload. Excess iron is deposited in organs such as the heart, the liver, the endocrine glands and the lungs.

OBJECTIVES

To evaluate the pulmonary functions in asymptomatic beta thalassemic children on regular transfusion therapy and their relation to iron overload.

METHODS

The study included 50 transfusion-dependent β-thalassemic children and 50 apparently healthy children as control. All children had undergone pulmonary function tests (spirometry, lung volumes and diffusion capacities). In addition, test to determine the mean serum ferritin of the last 2 years and pre-transfusion haemoglobin and chest radiograph and echocardiography were performed for the thalassemic children only.

RESULTS

A total of 70% of the thalassemic children had diffusion impairment, whereas 34% of them had associated restrictive abnormality. Thalassemic children with serum ferritin >2500 ng mL^-1 had significantly lower values of forced vital capacity (FVC), forced expiratory volume at one second (FEV1), peak expiratory flow (PEFR), total lung capacity (TLC) and diffusing capacity of carbon monoxide (DLCO) (P < 0·05). Only diffusion impairment had a significant positive correlation with serum ferritin level. Restrictive impairment had significant positive correlations with age, duration of blood transfusion and serum ferritin level and a significant negative correlation with duration of chelation (P < 0·05). Having a serum ferritin >2500 ng mL^-1 was the only predicting factor for diffusion impairment and the strongest predicting factor for restrictive dysfunction.

CONCLUSION

Despite being asymptomatic, the majority of thalassemic children in this study suffered from diffusion impairment either alone or in combination with restrictive dysfunction. These pulmonary dysfunctions correlated significantly with body iron stores measured by serum ferritin.

Pulmonary Functions in Children With Thalassemia Major

BACKGROUND

Thalassemia major (TM) is a chronic disease requiring regular transfusions that may result in generalized iron loading, such as in the heart, the liver, endocrine organs, and the lungs. We aimed to determine pulmonary function abnormalities in children with TM in our center.

PATIENTS AND METHODS

In this study, pulmonary function tests (PFTs) of 49 patients with TM who received regular blood transfusion and had no history of chronic respiratory disease were evaluated. The relationship between PFTs and the age, the body surface area, pretransfusional hemoglobin, and serum ferritin was evaluated.

RESULTS

Among the β-TM patients included in this study, 61% were male and 39% were female, with a mean age of 10.8±3 years (range, 5 to 17 y). The patients' mean level of ferritin was 3873±2011 ng/dL (range, 676 to 9476 ng/dL). A reduced forced vital capacity (FVC) was found in 33 patients (67%). A reduced forced expiratory volume in 1 second (FEV1) was found in 15 patients (30%). A forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) ratio of >80% was found in all patients. The peak expiratory flow (PEF) was decreased in 23 patients (46.9%). The forced mid-expiratory flow between 25% and 75% of the exhaled vital capacity (MEF25%-75%) was decreased in 5 patients (10%). FVC and FEV1 values in patients with a high ferritin level (>2500 ng/dL) were decreased compared with patients with a low ferritin level (<2500 ng/dL) (P=0.04, 0.03). FVC, FEV1, and PEF parameters were negatively correlated with the age and the body surface area. Age was a predictor of FVC (β=-0.450, P<0.001), FEV1 (β=-0.419, P<0.001), and PEF (β=-0.505, P<0.001), and hemoglobin was a predictor of FEV1/FVC (β=0.366, P=0.01) and MEF25%-75% (β=0.323, P=0.003).

CONCLUSIONS

Our results concluded that the respiratory system should be evaluated by PFTs even in asymptomatic patients with high serum ferritin levels during the adolescent period annually to prevent the squeal of pulmonary disease in TM. Patients who have abnormal PFTs should be reevaluated for compliance with chelation therapy and the transfusion program.

Effect of using bedside leukocyte filter on pulmonary functions in patients with thalassemia major

In settings of limited health resources, using leukocyte-filtered blood is limited to patients with leukocyte-mediated complications. The aim of this study was to determine the patterns of lung dysfunction among patients with β-thalassemia major (BTM) after the application of the leukostop filter during transfusion for a period of 6 months. The study included 30 patients with transfusion-dependent BTM divided into two groups according to the use of leukocyte filter. Group I included 15 patients with BTM allocated to use the leukocyte filter before each blood transfusion for 6 months and group II included 15 patients with BTM using nonleukocyte-filtered blood. Patients with history of airway disease and smokers were excluded. Chest X-ray and pulmonary function tests (PFT) using spirometry were done for each patient at baseline and after the use of the leukocyte filter for 6 months. No significant difference was found at baseline PFTs in both groups, the distribution of obstructive pulmonary disease significantly improved in group I in the postfilter evaluation, P < 0.05, however no change in pulmonary disease distribution in group II. A statistical significance improvement in forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1) and FEV1/FVC in postfilter evaluation, while in group II a decline in FEV1, FVC, and no significant change in FEV1/FVC ratio. There was no correlation between serum ferritin and PFT results.

CONCLUSION

Pulmonary function abnormalities, although subclinical is not an infrequent finding in patients with BTM; leukofiltred blood may improve PFT.

Cardiac and pulmonary dysfunction in asymptomatic beta-thalassanemia major

This study assessed cardiac and pulmonary dysfunction in 26 asymptomatic patients with beta-thalassemia major. This investigation was a case-controlled study considering 10-20-year-old patients with beta-thalassemia major and no cardiac or pulmonary symptoms. Healthy individuals matched for age and sex were used as controls. At 48-72 h after blood transfusion, the patients underwent echocardiography and spirometry by a cardiologist and a pulmonologist. The results were compared to those of the control group. The right and left myocardial performance index, preejection period/ejection time ratio, ejection fraction, acceleration time, isovolumic contraction time, and bilateral isovolumic relaxation times in the study group demonstrated significant differences from the data of the controls. Right deceleration time was significantly different between the 2 groups. Myocardial performance index, peak early velocity of the right heart, and peak atrial velocity-to-peak early velocity ratio of the right side by Doppler tissue imaging were also significantly different between the 2 groups. Spirometry showed a significant difference in forced expiratory volume in 1 s/forced vital capacity between groups. Based on spirometry, pulmonary involvement in the patients was 77% restrictive. These findings show that systolic and diastolic dysfunction of the heart and pulmonary disturbances are unavoidable in patients with beta-thalassemia major.

Restrictive pulmonary dysfunction and its predictors in young patients with β-thalassaemia major

BACKGROUND

Pulmonary dysfunction represents one of the most undervalued and less recognized complications in patients with β-thalassaemia.

OBJECTIVES

The aim of this study was to assess the pattern of pulmonary dysfunction and consequently to investigate possible associated factors that might contribute to lung impairment in young patients with β-thalassaemia major.

METHODS

Fifty-two children and young adults (mean age: 21.33 ± 6.24 years) with β-thalassaemia major on conventional treatment (transfusions and iron chelation therapy) were included in the study. A complete computerized pulmonary function testing (PFT) system for recording pulmonary diffusion capacity and simultaneous determination of alveolar volume and pulmonary volumes was equipped.

RESULTS

Results showed that 20 patients (38.46%) had restrictive pulmonary pattern that was preferentially observed in older and shorter patients. Serum ferritin levels were higher in the restrictive group (2,096 ± 1,831 ng/dl) compared to patients with normal pulmonary function (1,354 ± 942 ng/dl) (P = 0.066). Diffusional impairment characterized by significantly lower DLCO*% values, was observed in the restrictive group (P = 0.004), implicating the 62.5% of the population studied. Paired linear correlations showed that age was negatively correlated to DLCO*% (r = -0.548, P < 0.001) and SaO(2) % (r = -0.789, P < 0.001) and with most of the pulmonary functional parameters that determine a restrictive. Multivariate regression analysis identified age as the major predictor for restrictive pulmonopathy followed by serum ferritin levels.

CONCLUSIONS

Our study shows that pulmonary impairment is shown in a great proportion even among asymptomatic young thalassaemic patients, thus, regular screening of pulmonary function should be adopted in the routine clinical follow up of these patients.

Pulmonary function test in transfusion-dependent β-thalassemia major patients: a pilot study

Lung involvement is one of known complications of thalassemia. The aim of this study was to determine predominant type of pulmonary dysfunction and its relationship to iron overload in β-thalassemia children. Fifty thalassemia major children with treatment of regular blood transfusion and desferrioxamine participated in the study. Thirty-three boys and 17 girls (median age 12.5 years) with β-thalassemia enrolled in the study. Other information including body mass index, hematocrit, and the number of years of blood transfusion were recorded. Serum ferritin level and hematocrit were 3346 ± 1667 mg/dL and 27.7 ± 2, respectively. Pulmonary function tests were performed in all subjects for detecting pulmonary dysfunction. Thirty-five patients (70%) with thalassemia had abnormal result of spirometry. Obstructive airway disease based on reduced forced expiratory volume in 1 second (FEV(1)) and FEV(1)/forced vital capacity (FVC) ratio <80% was detected in 4 patients (8%). Six patients (12%) showed restrictive pattern, as defined by a reduction FVC <80% and FEV(1)/FVC ratio ≥80%. In this study, small airway involvement based on presence of forced expiratory flow (FEF(25%-75%)) <60%, FEV(1)/FVC ratio >70%, and FVC >80% was detected in 25 subjects (50%). Decreased values of peak expiratory flow rate (PEF) were detected in 23 (46%) and low FEV(1) in 10 (20%) subjects. There was no significant correlation between abnormal pulmonary function test and serum ferritin level in children with thalassemia. This study showed small airway disease was predominant abnormality in thalassemia patients, although additional larger studies are needed to evaluate underlying mechanisms and validate these findings.