JAK2 (V617F) mutation in healthy individuals.
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Adolescent↗
Biomedical subjects
Mario Cazzola
Publications and source records attributed to Mario Cazzola.
JAK2 (V617F) as an acquired somatic mutation and a secondary genetic event associated with disease progression in familial myeloproliferative disorders.
BACKGROUND: A somatic gain-of-function mutation of the Janus kinase 2 (JAK2) gene has been identified in chronic myeloproliferative disorders, which appear to have a sporadic occurrence in most individuals. The authors studied the biologic significance of the JAK2 (V617F) mutation in familial myeloproliferative disorders. METHODS: Twenty pedigrees with familial chronic myeloproliferative disorders were identified through an investigation of family history in 264 patients with sporadic myeloproliferative disorders. A quantitative real-time polymerase chain reaction (qRT-PCR)-based allelic discrimination assay was employed for the detection of the V617F mutation in circulating granulocytes and T lymphocytes. An analysis of X-chromosome inactivation pattern was performed in female patients. RESULTS: Fourteen families had homogeneous phenotypes, and 6 families had mixed phenotypes. By using a qRT-PCR-based allelic discrimination assay, the JAK2 (V617F) mutation was detected in circulating granulocytes from 20 of 31 patients, but the mutation was not detected in T lymphocytes. Granulocyte mutant alleles ranged from 2.1% to 91.5% and, on average, increased with time. Discordant distribution of the JAK2 (V617F) mutation was observed in siblings with polycythemia vera. The proportion of granulocytes that carried the JAK2 (V617F) mutation was lower than the proportion of clonal granulocytes, as determined in an analysis of X-chromosome inactivation patterns in female patients. CONCLUSIONS: The current findings indicated that the JAK2 (V617F) mutation represents an acquired somatic mutation in patients with familial chronic myeloproliferative disorders and probably occurs as a secondary genetic event in the background of preexisting clonal hematopoiesis. Thus, a genetic predisposition to acquisition of JAK2 (V617F) is inherited in families with myeloproliferative disorders.
Adolescent↗
The additive effect of theophylline on a combination of formoterol and tiotropium in stable COPD: a pilot study.
We explored the additive effect of titrated oral theophylline in patients with stable chronic obstructive pulmonary disease (COPD) who received both tiotropium, 18mug od, and formoterol, 12mug bid. Thirty-six patients with moderate-to-severe COPD were enrolled in this two-period trial. They were initially treated with formoterol+tiotropium for 4 weeks. After this first period, they were divided in two groups of 18 patients. Both groups continued with the initial treatment for further 4 weeks, but the first group received also placebo whereas the second group received oral theophylline. The combination therapy with formoterol+tiotropium induced a significant improvement in mean predose FEV(1) and FVC at the end of the first period, and a significant reduction in dyspnea score as measure by a visual analogic scale and in use of rescue salbutamol. The second period of treatment elicited a significant further improvement in lung function and reduction in dyspnea score and salbutamol use in both groups. On the contrary, differences in improvements in FEV(1) and FVC and reduction in dyspnea score and salbutamol use between theophylline and placebo arms at the end of the second treatment period were not significant, although 5 patients reported an important relief in dyspnea during the theophylline administration period. These findings question the importance of adding theophylline in stable COPD patients already treated with two long-acting bronchodilators, but also indicate the possibility that some of them can benefit from theophylline because of a symptomatic improvement.
Aged↗
A pilot study to assess the effects of combining fluticasone propionate/salmeterol and tiotropium on the airflow obstruction of patients with severe-to-very severe COPD.
The aim of this pilot study was to explore the relative efficacy in terms of improvement in symptoms and lung function of combining fluticasone propionate/salmeterol combination (FSC) and tiotropium in patients with severe-to-very severe stable COPD. Ninety patients were randomized to receive 3 months of treatment in one of three treatment groups: (1) FSC 500/50 microg Diskus, 1 inhalation twice daily+placebo Handihaler 1 inhalation once-daily daily; (2) tiotropium 18 microg Handihaler, 1 inhalation once daily+placebo Diskus, 1 inhalation twice daily; (3) FSC 500/50 microg Diskus, 1 inhalation twice daily+tiotropium 18 microg Handihaler, 1 inhalation once-daily daily. Patients attended the clinic before and after 1 month, 2 months, and 3 months of treatment for evaluations of pulmonary function, and dyspnea, which was assessed using a visual analog scale (VAS). Also the supplemental salbutamol use was measured. Eighty-one patients completed the 3-month treatment period: 26 patients receiving FSC, 26 patients receiving tiotropium, and 29 patients receiving FSC+tiotropium. Patients were withdrawn for COPD exacerbation. Improvements in trough FEV(1) with all treatments medications were observed by the first month when trough FEV(1) had improved significantly above baseline by 74 mL (p<0.05) in the tiotropium group, by 117 mL (p<0.05) in the FSC group and by 115 mL (p<0.05) in FSC+tiotropium group. At the end of the study, trough FEV(1) had improved significantly above baseline by 141 mL (p<0.05) in the tiotropium group, by 140 mL (p<0.05) in the FSC group and by 186 mL (p<0.05) in FSC+tiotropium group. The difference between FSC and tiotropium appeared to decrease, that between FSC and FSC+tiotropium appeared to increase and that between tiotropium and FSC+tiotropium remained almost similar with study duration. Our results suggest that adding FSC and tiotropium may provide benefits in symptomatic patients with severe-to-very severe stable COPD.
Administration, Inhalation↗
[Hyperferritinemia-cataract syndrome associated to the HFE gene mutation. Two new Spanish families and a new mutation (A37T: "Zaragoza")].
BACKGROUND AND OBJECTIVE: Nuclear congenital cataracts associated with hyperferritinemia--hereditary hyperferritinemia cataract syndrome (HHCS)--without clinical or biochemical signs of iron overload have been recently described in several Spanish families. This HHCS is associated with mutations in the gene of ferritin subunit L, located in chromosome 19. We describe 2 new families with HHCS, one of them presenting a new L-ferritin mutation (A37T: -Zaragoza-). PATIENTS AND METHOD: Patients and probands were studied according to the Anemia Unit protocol: complete blood count, biochemical profile (diabetes, hepatic and renal), hepatic serologies, iron metabolism (iron, transferrin, ferritin, transferrin saturation, reactive C protein) and mutation HFE gene studies (C282Y, H63D). All of them were sent to the Ophthalmology Service for cataract study. L-ferritin mutational scanning was performed by denaturing high performance liquid chromatography (DHPLC). Samples displaying an altered elution profile, as compared to a wild type control, were directly sequenced for the precise characterization of the L-ferritin mutation. RESULTS: Family A proband was a 54 year-old-female, with cataracts, ferritin level: 942 pg/I, transferrin saturation: 14%, HFE gen study: H63D/H63D; L-ferritin gene study: C33T mutation/-. Her two sons had cataracts, hyperferritinemia (1607, and 1188 pg/I, respectively), normal transferrin saturation (40% and 9%), HFE gene study: H63D/N; and L-ferritin gen study: C33T/-. Family B proband was a 39 year-old-female, with cataract, ferritin level: 636 pg/I, transferrin saturation: 25%, HFE gene study: H63D/N; and L-ferritin gene study: A37T/-. Her two sons, sister, brother and nephew, who were affected with A37T mutation, showed hyperferritinemia (883, 747, 835, 613 and 1396 pg/I) with normal transferrin saturation levels (17%, 34%, 25%, 18% and 24%); but the ferritin levels of those non-affected were normal (35 and 50 pg/I). CONCLUSIONS: HHCS is a dominant autosomic condition, with a possible world-wide distribution,which should be included in the differential diagnosis of hyperferritinemia studies. It is important to suspect it in order to avoid wrong treatment.
Adolescent↗
Additional clinical benefit of enoxaparin in COPD patients receiving salmeterol and fluticasone propionate in combination.
It is now well recognised that heparin possesses numerous anti-inflammatory properties in addition to its anticoagulant properties. Thus, the aim of this study was to investigate the effects of the low molecular weight heparin, enoxaparin (ENX), as an add-on therapy for a period of 12 weeks, to inhaled salmeterol/fluticasone propionate (SLM/FP) combination in patients with stable chronic obstructive pulmonary disease (COPD). Forty-six patients were randomised to receive 12 weeks of treatment in one of two treatment groups: (1) fixed combination of SLM 50 microg and FP 500 microg Diskus, one inhalation twice daily; or (2) as group 1 plus 20 mg ENX administered subcutaneously once daily for 12 weeks. Patients attended the clinic before and after 4, 8 and 12 weeks of treatment for evaluations of lung function, blood gas tensions, dyspnoea and supplemental salbutamol use. Thirty-six patients completed the 12-week treatment period, 20 from group 1 and 16 from group 2. A significant increase in forced expiratory volume in 1 s (FEV1) over baseline was observed after 12 weeks of treatment in group 1 (0.145 L, 95% CI: 0.994-1.406, p<0.01), whilst significant increases in FEV1 over baseline were observed in group 2 after 4, 8 and 12 weeks of treatment with a maximum increase at 12 weeks of 0.244 L (95% CI: 1.175-1.596, p<0.01). Both treatment groups experienced similar improvements in blood gas tensions, dyspnoea and supplemental salbutamol use. Our results suggest that addition of ENX to conventional therapy of COPD may provide additional clinical benefit and must be further investigated as a treatment for COPD.
Aged↗
Markers of exacerbation severity in chronic obstructive pulmonary disease.
BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) can experience 'exacerbations' of their conditions. An exacerbation is an event defined in terms of subjective descriptors or symptoms, namely dyspnoea, cough and sputum that worsen sufficiently to warrant a change in medical management. There is a need for reliable markers that reflect the pathological mechanisms that underlie exacerbation severity and that can be used as a surrogate to assess treatment effects in clinical studies. Little is known as to how existing study variables and suggested markers change in both the stable and exacerbation phases of COPD. In an attempt to find the best surrogates for exacerbations, we have reviewed the literature to identify which of these markers change in a consistent manner with the severity of the exacerbation event. METHODS: We have searched standard databases between 1966 to July 2004 using major keywords and terms. Studies that provided demographics, spirometry, potential markers, and clear eligibility criteria were included in this study. Central tendencies and dispersions for all the variables and markers reported and collected by us were first tabulated according to sample size and ATS/ERS 2004 Exacerbation Severity Levels I to III criteria. Due to the possible similarity of patients in Levels II and III, the data was also redefined into categories of exacerbations, namely out-patient (Level I) and in-patient (Levels II & III combined). For both approaches, we performed a fixed effect meta-analysis on each of the reported variables. RESULTS: We included a total of 268 studies reported between 1979 to July 2004. These studies investigated 142,407 patients with COPD. Arterial carbon dioxide tension and breathing rate were statistically different between all levels of exacerbation severity and between in out- and in-patient settings. Most other measures showed weak relationships with either level or setting, or they had insufficient data to permit meta-analysis. CONCLUSION: Arterial carbon dioxide and breathing rate varied in a consistent manner with exacerbation severity and patient setting. Many other measures showed weak correlations that should be further explored in future longitudinal studies or assessed using suggested mathematical modelling techniques.
Arteries↗
Are phosphodiesterase 4 inhibitors just more theophylline?
Theophylline has been relegated to a second- or even third-line therapy in the treatment of asthma and chronic obstructive pulmonary disease (COPD), behind glucocorticosteroids and beta2-agonists, although recent findings have suggested that theophylline possesses anti-inflammatory and immunomodulatory effects in addition to its well-recognized effects as a bronchodilator. In part, theophylline has fallen out of favor because of its adverse side-effect profile, and this has led to the search for more effective and safer drugs based on the knowledge that theophylline is orally active and that it is a nonselective phosphodiesterase (PDE) inhibitor. This has led to the development of selective PDE4 inhibitors, originally designed for depression, for the treatment of both COPD and asthma. Such drugs have shown clinical efficacy in the treatment of respiratory disease while having a considerably safer side-effect profile in comparison with theophylline, particularly because there are no reported drug interactions with PDE4 inhibitors, a feature that complicates the use of theophylline. In addition, it is also becoming increasingly apparent that theophylline is not working solely through PDE inhibition, as formerly assumed, and that this drug has other relevant pharmacologic activities that are likely to contribute to its efficacy, such as adenosine receptor antagonism and induction of histone deacetylase. Thus, the introduction of PDE4 inhibitors represents an entirely new class of drugs for the treatment of respiratory disease.
3',5'-Cyclic-AMP Phosphodiesterases↗
Effect of formoterol, tiotropium, and their combination in patients with acute exacerbation of chronic obstructive pulmonary disease: a pilot study.
The aim of our study was to evaluate the pharmacodynamic effects of 1-day treatment with formoterol, tiotropium and their combination in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Twenty-one (19 males, mean age 72+/-8 years, mean FEV1 38+/-14% of predicted values) patients with mild to moderate AECOPD were enrolled. Patients received formoterol (12 microg deliver via Modulite b.i.d.), tiotropium (18 microg dry powder capsules delivered via HandiHaler once daily), and their combination, in randomized sequence. Serial measurements of FEV1, FVC, IC, SpO2 and HR were performed over 24h. Formoterol, tiotropium, and their combination significantly improved the area under curves (AUCs) for FEV1, FVC and IC over 12 and 24h. The mean FEV1, FVC and IC AUC(0-12h) and AUC(0-24h) after formoterol and tiotropium combination were significantly higher than formoterol and tiotropium alone, whereas the differences between the two single drugs were not statistically significant. Formoterol, either alone or in combination with tiotropium, elicited a significantly faster onset of action, and combination elicited a greater maximum bronchodilation than both single drugs in terms of FEV1 and FVC. After 24h the bronchodilating effect of the three treatments disappeared, with the exception of the combination on FEV1. The results of this study have documented that, although the time course of the effects of evaluated drugs differs significantly from that in stable COPD, with a shorter bronchodilation both for tiotropium and formoterol, these two long-acting bronchodilators appear to also be complementary in mild to moderate AECOPD.
Acute Disease↗
Survivin expression, apoptosis and proliferation in chronic myelomonocytic leukemia.
We analyzed the expression of the inhibitor of apoptosis survivin by immunocytochemistry in bone marrow cells from patients with chronic myelomonocytic leukemia (CMML) to evaluate possible abnormalities in comparison with other myelodysplastic (MDS) and myeloproliferative syndromes, and to investigate a possible correlation between survivin expression and altered apoptosis or proliferation, or relevant laboratory and clinical findings. Thirty-four patients with CMML [18 MDS-CMML and 16 myeloproliferative disorder (MPD)-CMML], 90 with MDS, 41 with acute myeloid leukemia (AML), 19 with chronic MPD and 25 control subjects were studied. In normal samples survivin was never detectable. In CMML survivin levels higher than in MDS and AML (P < 0.0001), but similar to those found in MPD were observed. In CMML and MDS apoptosis was significantly higher compared to normal controls and all other subtypes of leukemias (P < 0.0001). Proliferation did not differ significantly in normal controls, MDS and CMML; the lowest levels were observed in AML and MPD (P < 0.0001). In CMML there was no correlation between survivin expression and blast cell percentage, apoptosis or proliferation, FAB or WHO subgroup. Proliferation was higher in MDS-CMML and tended to correlate with overall survival. CMML-2 cases with higher survivin expression showed higher evolution rate and shorter survival. In conclusion, CMML is characterized by high proliferation and apoptosis. Survivin overexpression, by disrupting the balance between cell proliferation/differentiation and apoptosis, may play an important role in its pathophysiology. The detection of survivin-deregulated expression may provide a useful tool for diagnosis, prognosis and a possible target for experimental treatments.
Acute Disease↗
Gene expression profiles of CD34+ cells in myelodysplastic syndromes: involvement of interferon-stimulated genes and correlation to FAB subtype and karyotype.
To gain insight into the poorly understood pathophysiology of the myelodysplastic syndromes (MDSs), we have determined the gene expression profiles of the CD34+ cells of 55 patients with MDS by using a comprehensive array platform. These profiles showed many similarities to reported interferon-gamma-induced gene expression in normal CD34+ cells; indeed the 2 most up-regulated genes, IFIT1 and IFITM1, are interferon-stimulated genes (ISGs). Alterations in the expression of ISGs may play a role in the hematologic features of MDS, such as peripheral blood cytopenias. Up-regulation of IFIT1 is a potential diagnostic marker for MDS. We determined whether distinct gene expression profiles were associated with specific FAB and cytogenetic groups. CD34+ cells from patients with refractory anemia with ringed sideroblasts (RARS) showed a particular gene expression profile characterized by up-regulation of mitochondrial-related genes and, in particular, of those of heme synthesis (eg, ALAS2). CD34+ cells from patients with the del(5q) had a distinct gene expression profile, characterized by down-regulation of genes assigned to 5q, and up-regulation of the histone HIST1 gene cluster at chromosome 6p21 and of genes related to the actin cytoskeleton. This study provides important and new insights into the pathophysiology of MDS.
Adaptor Proteins, Signal Transducing↗
Doppler echocardiographic assessment of the effects of inhaled long-acting beta2-agonists on pulmonary artery pressure in COPD patients.
Increase in pulmonary artery pressure (PAP), which is common in severe chronic obstructive pulmonary disease (COPD), is a predictor of mortality independent of airflow limitation. beta-agonists might slightly attenuate this increase because they exert a vasodilating effect on pulmonary circulation when systematically administered. We have investigated the acute effects of salmeterol and formoterol on echocardiographic systolic pulmonary artery pressure (sPAP) in 20 patients with COPD and a sPAP greater than 20mmHg at rest. Acute haemodynamic responses to inhaled formoterol or salmeterol were assessed in all patients, in a randomized, double-blind double-dummy fashion. On two consecutive days, patients received, in a randomized order, formoterol 12microg via Turbuhaler plus placebo via Diskus or salmeterol 50microg via Diskus plus placebo via Turbuhaler. Transthoracic Doppler echocardiography measurements of sPAP were made before and 15, 30, 60 and 180min after bronchodilator inhalation. Lung function, pulse oximetry and heart rate were also monitored at the same times. Mean sPAP significantly (p<0.05) decreased in comparison with baseline at 15, 30, and 60min post inhalation but returned towards control levels at 180min after both salmeterol and formoterol. There was no correlation between the maximum increase in FEV(1) and maximum decrease in sPAP either after inhalation of salmeterol (r(2)=0.071) or after that of formoterol (r(2)=0.0006). The increases in FEV(1) in comparison with baseline were always significant (p<0.05) from 15 to 180min post inhalation after either salmeterol or formoterol. Neither pulse oximetry nor heart rate changed in a significant manner (p>0.05). This study demonstrated that salmeterol and formoterol were equally beneficial for pulmonary haemodynamics in patients with COPD. A direct vasodilatation due to the activation of beta-adrenoceptors that are present in pulmonary vessels is a likely mechanism of their action in inducing the decrease in sPAP.
Administration, Inhalation↗
Evidence of angiogenesis in bronchial biopsies of smokers with and without airway obstruction.
The involvement of bronchial vasculature in the airway remodelling occurring in symptomatic smokers with normal lung function and with chronic obstructive pulmonary disease (COPD) has been poorly investigated. An immunohistochemical study was performed on bronchial biopsies taken from 8 non-smokers and 18 smokers divided, according to global health initiative on obstructive lung diseases (GOLD) classification of COPD, into two groups, GOLD 0 and GOLD 2, each of 9 subjects. The number of vessels and the percentage of vascular area in the lamina propria were evaluated by mAb anti-collagen IV. Cellular expression of VEGF and vascular expression of alphavbeta3 integrin were evaluated by the specific monoclonal antibodies. An image processing and analysis system was used to quantify the immunohistochemical data. The number of vessels, the vascular area, the cellular expression of VEGF, the number and percentage of alphavbeta3 positive vessels were significantly higher in GOLD 0 and in GOLD 2 smokers than in non-smokers. The comparison between GOLD 0 and GOLD 2 smokers did show a weak but significantly lower number of vessels in GOLD 2, while the vascular area and the percentage of alphavbeta3 positive vessels did not differ between the two groups. A higher cellular VEGF expression was detected in the GOLD 2 than in the GOLD 0 group. Angiogenesis of bronchial vessels is a component of the airway remodelling occurring in symptomatic smokers with normal lung function and with COPD, it seems independent by the development of airway obstruction and not related to its severity.
Biopsy↗
Dyspnea secondary to pulmonary hematopoiesis as presenting symptom of myelofibrosis with myeloid metaplasia.
We report a case of a patient with myelofibrosis with myeloid metaplasia (MMM) who presented with progressive dyspnea of unexplained origin. Splenomegaly, blood smear, and bone marrow findings allowed diagnosis of MMM. High-resolution CT chest scan revealed diffuse septal thickening, while echocardiography and electrocardiogram showed no indirect evidence of pulmonary hypertension. Finally, lung biopsy revealed irregularly distributed interstitial fibrosis with islands of erythroblasts, immature granulocytic elements, and dysplastic megakaryocytes, allowing diagnosis of pulmonary extramedullary hematopoiesis (EMH). The patient received hydroxyurea as cytoreductive agent, obtaining a good hematologic response and an improvement of dyspnea. Note that, in this patient, dyspnea was the first clinical symptom of MMM; the dyspnea was not associated with pulmonary hypertension and improved following cytoreductive treatment. This case points to the importance of suspecting pulmonary EMH when unexplained progressive dyspnea occurs in a patient with MMM. Early recognition of pulmonary EMH may prevent PH and favor a better response to therapy.
Biopsy↗
Microelectronic DNA chip for hereditary hyperferritinemia cataract syndrome, a model for large-scale analysis of disorders of iron metabolism.
Hereditary hyperferritinemia cataract syndrome (HHCS) is caused by mutations in the regulatory iron responsive element (IRE) in the 5'UTR of the L-ferritin transcript that reduce binding affinity to the iron regulatory proteins (IRPs) and lead to a constitutive upregulation of the protein in tissue and serum. Twenty-nine mutations have been reported within the L-ferritin (FTL) IRE sequence, 21 of which were available to us. In addition, we included in this study three new mutations. Thus, we analyzed 24 mutations spanning over a DNA stretch of 48 nucleotides, including four deletions 2-29 nucleotides long and 20 substitutions, seven of which were conservative transversions. With this unique experimental model we developed a microchip diagnostic platform for identifying known molecular defects in the L-ferritin IRE structure with a microelectronic array approach, which we optimized after studying the effects of various parameters. The system enables electronic deposition of biotinylated amplicons to selected pads. Under optimized conditions, no cross-hybridization was found, even for mutations that affected the same or adjacent nucleotide positions. The same cartridge could be serially hybridized with all the 24 reporter probe sets, which allowed correct genotyping right up until the end of the analysis. Extensive validation on 200 samples in a blinded fashion gave total concordance of results. This pilot study represents a first step toward developing a diagnostic microchip for large-scale analyses for epidemiological studies and screening of mutations associated with iron disorders.
5' Untranslated Regions↗
Anti-TNF-alpha and Th1 cytokine-directed therapies for the treatment of asthma.
PURPOSE OF REVIEW: This article examines recent work about the role of TNF-alpha and of selected Th1-related cytokines in asthma with particular emphasis on the therapeutic potential of blocking the biological activity of these mediators. RECENT FINDINGS: Current research endeavours suggest that asthma pathogenesis is driven by a mixed Th1/Th2 immune response. The contribution of individual Th1-associated and Th2-associated effector mechanisms to this mixed response profile is highly heterogeneous and variations in response patterns seem to be associated with heterogeneity in clinical phenotypes. In particular, it is now acknowledged that allergen-specific Th1 responses appear to be responsible for the pathogenetic effects seen in patients suffering from the more severe chronic forms of the disease. This is important because usual treatments for asthma appear to have limited effects on the more chronic severe forms of the disease and there is a pressing need for the development of new treatment strategies. The failure of topical corticosteroids to reduce TNF-alpha and Th1-derived cytokines to a significant level in asthmatic airways may explain to a certain extent why these drugs appear to have limited effects in the more severe forms of asthma. SUMMARY: It is likely that therapies blocking TNF-alpha and interfering with Th1-derived cytokines may be a considerable advance in the management of those asthma patients who are particularly resistant to typical treatment modalities.
Animals↗
Should the choice of a long-acting bronchodilator in the long-term therapy of chronic obstructive pulmonary disease depend entirely on the onset of action?
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Bronchodilator Agents↗
Application of Number Needed to Treat (NNT) as a Measure of Treatment Effect in Respiratory Medicine.
Presentation of clinical data can have a profound effect on treatment decisions, and there is a need for measures that are objective, have clinical relevance, and are easily interpreted. Relative risk is often used to summarize treatment comparisons, but does not account for variations in baseline risk profiles and does not convey information on absolute sizes of treatment effects. Absolute risk reduction gives this information, but the data are dimensionless and abstract, and lack a direct connection with the clinical environment.The number needed to treat, or NNT, has been developed to address this issue. NNT is the reciprocal of the absolute risk reduction associated with an intervention, and may also be calculated as 100 divided by the absolute risk reduction expressed as a percentage. The result is the number of patients who would have to receive treatment for one of them to benefit or to avoid an adverse outcome over a given period of time. Since its introduction, the concept of NNT has been expanded to include number needed to harm (NNH), which illustrates adverse events or other undesirable outcomes associated with treatment, and the epidemiologic tool of number needed to screen.NNT has been used to describe treatment effects from many clinical trials. A recent example illustrates benefit of inhaler therapy combining a long-acting beta(2)-agonist (LABA) and corticosteroid for COPD over treatment with LABA alone. NNT has also been extended to systematic reviews and meta-analyses, where it has been used to rank different treatments where baseline profiles, treatment outcomes and time periods under examination are similar.NNT is therefore a concise and easily understood tool for quantifying treatment efficacy, particularly when applying trial results to the clinic setting.
Adrenal Cortex Hormones↗