Spatiotemporal changes in aerosols over Bangladesh using 18 years of MODIS and reanalysis data.

In this study, combined Dark Target and Deep Blue (DTB) aerosol optical depth at 550 nm (AOD550 nm) data the Moderate Resolution Imaging Spectroradiometer (MODIS) flying on the Terra and Aqua satellites during the years 2003-2020 are used as a reference to assess the performance of the Copernicus Atmosphere Monitoring Services (CAMS) and the second version of Modern-Era Retrospective analysis for Research and Applications (MERRA-2) AOD over Bangladesh. The study also investigates long-term spatiotemporal variations and trends in AOD, and determines the relative contributions from different aerosol species (black carbon: BC, dust, organic carbon: OC, sea salt: SS, and sulfate) and anthropogenic emissions to the total AOD. As the evaluations suggest higher accuracy for CAMS than for MERRA-2, CAMS is used for further analysis of AOD over Bangladesh. The annual mean AOD from both CAMS and MODIS DTB is high (>0.60) over most parts of Bangladesh except for the eastern areas of Chattogram and Sylhet. Higher AOD is observed in spring and winter than in summer and autumn, which is mainly due to higher local anthropogenic emissions during the winter to spring season. Annual trends from 2003-2020 show a significant increase in AOD (by 0.006-0.014 year-1) over Bangladesh, and this increase in AOD was more evident in winter and spring than in summer and autumn. The increasing total AOD is caused by rising anthropogenic emissions and accompanied by changes in aerosol species (with increased OC, sulfate, and BC). Overall, this study improves understanding of aerosol pollution in Bangladesh and can be considered as a supportive document for Bangladesh to improve air quality by reducing anthropogenic emissions.

Estimating surface visibility at Hong Kong from ground-based LIDAR, sun photometer and operational MODIS products.

Hong Kong's surface visibility has decreased in recent years due to air pollution from rapid social and economic development in the region. In addition to deteriorating health standards, reduced visibility disrupts routine civil and public operations, most notably transportation and aviation. Regional estimates of visibility solved operationally using available ground and satellite-based estimates of aerosol optical properties and vertical distribution may prove more effective than standard reliance on a few existing surface visibility monitoring stations. Previous studies have demonstrated that such satellite measurements correlate well with near-surface optical properties, despite these sensors do not consider range-resolved information and indirect parameterizations necessary to solve relevant parameters. By expanding such analysis to include vertically resolved aerosol profile information from an autonomous ground-based lidar instrument, this work develops six models for automated assessment of surface visibility. Regional visibility is estimated using co-incident ground-based lidar, sun photometer visibility meter and MODerate-resolution maging Spectroradiometer (MODIS) aerosol optical depth data sets. Using a 355 nm extinction coefficient profile solved from the lidar MODIS AOD (aerosol optical depth) is scaled down to the surface to generate a regional composite depiction of surface visibility. These results demonstrate the potential for applying passive satellite depictions of broad-scale aerosol optical properties together with a ground-based surface lidar and zenith-viewing sun photometer for improving quantitative assessments of visibility in a city such as Hong Kong.

Monitoring the Sea Surface Microlayer (SML) on Sentinel images.

Slicks on the sea surface are usually related to oil spills, algal blooms or organic runoff around coastlines. An extensive network of slicks extending across the English Channel is seen on Sentinel 1 and Sentinel 2 images and are identified as comprising a film of natural surfactant material within the sea surface microlayer (SML). As the SML represents the interface between ocean and atmosphere, controlling the vital exchange of gases and aerosols, identification of the slicks on images can add a new dimension to climate modelling. Current models use primary productivity often combined with wind speed, but quantifying the global extent of surface films spatially and temporally is difficult due to their patchy nature. The slicks are shown to be visible on Sentinel 2 optical images affected by sun glint, due to the wave dampening effect of the surfactants. On a Sentinel 1 SAR image of the same day, they can be identified using the VV polarised band. The paper investigates the nature and spectral properties of the slicks in relation to sun glint, and evaluates the performance of chlorophyll-a, floating algae and floating debris indices on the slick-affected areas. No index was able to distinguish slicks from non-slick areas as successfully as the original sun glint image. This image was used to devise a tentative Surfactant Index (SI) which indicates over 40 % of the study area covered by slicks. As ocean sensors have lower spatial resolution and are generally designed to avoid sun glint, Sentinel 1 SAR may offer a useful alternative for monitoring the global spatial extent of surface films, until dedicated sensors and algorithms can be developed.

Long-term PM2.5 pollution over China: Identification of PM2.5 pollution hotspots and source contributions.

Fine particulate matter, with an aerodynamic diameter ≤ 2.5 µm (PM2.5), is a severe problem in China. The lack of ground-based measurements and its sparse distribution obstruct long-term air pollution impact studies over China. Therefore, the present study used newly updated Global Estimates (V5. GL.02) of monthly PM2.5 data from 2001 to 2020 based on Geographically Weighted Regression (GWR) by Washington University. The GWR PM2.5 data were validated against ground-based measurements from 2014 to 2020, and the validation results demonstrated a good agreement between GWR and ground-based PM2.5 with a higher correlation (r = 0.95), lower error (8.14), and lower bias (-3.10 %). The long-term (2001-2020) PM2.5 data were used to identify pollution hotspots and sources across China using the potential source contribution function (PSCF). The results showed highly significant PM2.5 pollution hotspots in central (Henan, Hubei), North China Plain (NCP), northwest (Taklimakan), and Sichuan Basin (Chongqing, Sichuan) in China, with the most severe pollution occurring in winter compared to other seasons. During the winter, PM2.5 was in the range from 6.08 to 93.05 µg/m3 in 33 provinces, which is 1.22 to 18.61 times higher than the World Health Organization (WHO) Air Quality Guidelines (AQG-2021; annual mean: 5 µg/m3). In 26 provinces, the reported PM2.5 was 1.07 to 2.66 times higher than the Chinese Ambient Air Quality Standard (AAQS; annual mean: 35 µg/m3). Furthermore, provincial-level trend analysis shows that in most Chinese provinces, PM2.5 increased significantly (3-43 %) from 2001 to 2012, whereas it decreased by 12-94 % from 2013 to 2020 due to the implementation of air pollution control policies. Finally, the PSCF analysis demonstrates that China's air quality is mainly affected by local PM2.5 sources rather than by pollutants imported from outside China.

Comment on Abdul Jabbar et al. Air Quality, Pollution and Sustainability Trends in South Asia: A Population-Based Study. Int. J. Environ. Res. Public Health 2022, 19, 7534.

This comment discusses the use of PM2.5 (mass concentration of fine particulate matter with an aerodynamic diameter less than 2.5 microns) data in the recently published article entitled "Air Quality, Pollution and Sustainability Trends in South Asia: A Population-Based Study" by Abdul Jabbar et al. [...].

Safety and efficacy of long-term treatment with romiplostim in thrombocytopenic patients with chronic ITP.

Chronic immune thrombocytopenic purpura (ITP) is characterized by low platelet counts and mucocutaneous bleeding. In previous studies romiplostim (AMG531), a thrombopoiesis-stimulating protein, increased platelet counts in most patients with chronic ITP. This ongoing, long-term open-label, single-arm study investigated safety and efficacy in patients who completed a previous romiplostim study and had platelet counts less than or equal to 50 [corrected] x 10(9)/L. One hundred forty-two patients were treated for up to 156 weeks (mean, 69 weeks). Platelet responses (platelet count > or = 50 x 10(9)/L and double baseline) were observed in 87% of all patients and occurred on average 67% of the time in responding patients. In 77% of patients, the romiplostim dose remained within 2 microg/kg of their most frequent dose at least 90% of the time. Ninety patients (63%) received treatment by self-administration. Treatment-related serious adverse events were reported in 13 patients (9%). Bone marrow reticulin was observed in 8 patients; marrows were not routinely performed in this study, so the true incidence of this event cannot be determined. Severe bleeding events were reported in 12 patients (9%). Thrombotic events occurred in 7 patients (5%). In conclusion, romiplostim increased platelet counts in most patients for up to 156 weeks without tachyphylaxis and had an acceptable safety profile. (ClinicalTrials.gov Identifier NCT00116688).

Trends in vegetation productivity related to climate change in China's Pearl River Delta.

Climate change will be a powerful stressor on ecosystems and biodiversity in the second half of the 21st century. In this study, we used the satellite-derived Normalized Difference Vegetation Index (NDVI) to examine a 34-year trend along with the response of vegetation to climate indicators surrounding the world's largest megacity: the Pearl River Delta (PRD) of China. An overall increasing trend is observed in vegetation productivity metrics over the study period 1982 to 2015. Increase in winter productivity in both natural ecosystems and croplands is more related to increasing temperatures (r = 0.5-0.78), than to changes in rainfall. For growing season productivity, negative correlations with temperature were observed in cropland regions, and some forests in the northern part of PRD region, suggesting high-temperature stress on crop production and forest vegetation. However, increased winter and spring temperatures provide higher opportunities for cropping in winter. During the decade 1995-2004, vegetation productivity metrics showed a reversal in the upward trend. The geographical and biological complexity of the region under significant climatic and development impacts suggests causative factors would be synergistic. These include our observed decrease in sunshine hours, increasing cloud cover associated with atmospheric aerosols from industrial and urban development, direct pollution effects on plant growth, and exceedance of high temperature growth thresholds.

Spatial and environmental constraints on natural forest regeneration in the degraded landscape of Hong Kong.

Tropical forests are the main reservoirs for global biodiversity and climate control. As secondary forests are now more widespread than primary forests, understanding their functioning and role in the biosphere is increasingly important. This includes understanding how they achieve stability, how they accumulate species and build biodiversity and how they cycle nutrients and carbon. This study investigates how we can restore tropical secondary forests to resemble high biomass, highly biodiverse and stable ecosystems seen today only in primary, undisturbed forests. The study used historic aerial photographs and recent high-resolution satellite images from 1945 to 2014 to map forest patches with five age categories, from 14-years to over 70-years, in Hong Kong's degraded tropical landscape. A forest inventory comprising 28 quadrats provided a rare opportunity to relate patterns of species composition at different stages during the succession with topographic and soil characteristics. The topographic variables accounted for 15% of the variance in species abundance, and age of forest stands explained 29%. Species richness rapidly increased after the first 15 years, but was lower in old-growth, than in medium age forest. This is attributed to the inability of late-successional species to disperse into the young forests as the natural dispersal agents (birds, mammals) have been lost. Light-loving pioneers which are unable to tolerate the shade of older forests, cannot regenerate in their own shade, therefore species diversity declines after a few decades. For ecosystem restoration in tropical secondary forests, introduction of late-successional species is necessary to assist natural succession, given the absence of native fauna, seed dispersal agents, and the surrounding altered environment. We also show that remote sensing can play a pivotal role in understanding the recovery and functioning of secondary forest regeneration as its contribution to the biosphere is increasingly important.

Spatial analysis of the impact of urban geometry and socio-demographic characteristics on COVID-19, a study in Hong Kong.

The World Health Organization considered the wide spread of COVID-19 over the world as a pandemic. There is still a lack of understanding of its origin, transmission, and treatment methods. Understanding the influencing factors of COVID-19 can help mitigate its spread, but little research on the spatial factors has been conducted. Therefore, this study explores the effects of urban geometry and socio-demographic factors on the COVID-19 cases in Hong Kong. For each patient, the places they visited during the incubation period before going to hospital were identified, and matched with corresponding attributes of urban geometry (i.e., building geometry, road network and greenspace) and socio-demographic factors (i.e., demographic, educational, economic, household and housing characteristics) based on the coordinates. The local cases were then compared with the imported cases using stepwise logistic regression, logistic regression with case-control of time, and least absolute shrinkage and selection operator regression to identify factors influencing local disease transmission. Results show that the building geometry, road network and certain socio-economic characteristics are significantly associated with COVID-19 cases. In addition, the results indicate that urban geometry is playing a more important role than socio-demographic characteristics in affecting COVID-19 incidence. These findings provide a useful reference to the government and the general public as to the spatial vulnerability of COVID-19 transmission and to take appropriate preventive measures in high-risk areas.

Pathogenesis of chronic immune thrombocytopenia: increased platelet destruction and/or decreased platelet production.

Chronic immune thrombocytopenia (ITP) is a haematological disorder in which patients predominantly develop skin and mucosal bleeding. Early studies suggested ITP was primarily due to immune-mediated peripheral platelet destruction. However, increasing evidence indicates that an additional component of this disorder is immune-mediated decreased platelet production that cannot keep pace with platelet destruction. Evidence for increased platelet destruction is thrombocytopenia following ITP plasma infusions in normal subjects, in vitro platelet phagocytosis, and decreased platelet survivals in ITP patients that respond to therapies that prevent in vivo platelet phagocytosis; e.g., intravenous immunoglobulin G, anti-D, corticosteroids, and splenectomy. The cause of platelet destruction in most ITP patients appears to be autoantibody-mediated. However, cytotoxic T lymphocyte-mediated platelet (and possibly megakaryocyte) lysis, may also be important. Studies supporting suppressed platelet production include: reduced platelet turnover in over 80% of ITP patients, morphological evidence of megakaryocyte damage, autoantibody-induced suppression of in vitro megakaryocytopoiesis, and increased platelet counts in most ITP patients following treatment with thrombopoietin receptor agonists. This review summarizes data that indicates that the pathogenesis of chronic ITP may be due to both immune-mediated platelet destruction and/or suppressed platelet production. The relative importance of these two mechanisms undoubtedly varies among patients.

Efficacy of romiplostim in patients with chronic immune thrombocytopenic purpura: a double-blind randomised controlled trial.

BACKGROUND: Chronic immune thrombocytopenic purpura (ITP) is characterised by accelerated platelet destruction and decreased platelet production. Short-term administration of the thrombopoiesis-stimulating protein, romiplostim, has been shown to increase platelet counts in most patients with chronic ITP. We assessed the long-term administration of romiplostim in splenectomised and non-splenectomised patients with ITP. METHODS: In two parallel trials, 63 splenectomised and 62 non-splenectomised patients with ITP and a mean of three platelet counts 30x10(9)/L or less were randomly assigned 2:1 to subcutaneous injections of romiplostim (n=42 in splenectomised study and n=41 in non-splenectomised study) or placebo (n=21 in both studies) every week for 24 weeks. Doses of study drug were adjusted to maintain platelet counts of 50x10(9)/L to 200x10(9)/L. The primary objectives were to assess the efficacy of romiplostim as measured by a durable platelet response (platelet count > or =50x10(9)/L during 6 or more of the last 8 weeks of treatment) and treatment safety. Analysis was per protocol. These studies are registered with ClinicalTrials.gov, numbers NCT00102323 and NCT00102336. FINDINGS: A durable platelet response was achieved by 16 of 42 splenectomised patients given romplostim versus none of 21 given placebo (difference in proportion of patients responding 38% [95% CI 23.4-52.8], p=0.0013), and by 25 of 41 non-splenectomised patients given romplostim versus one of 21 given placebo (56% [38.7-73.7], p<0.0001). The overall platelet response rate (either durable or transient platelet response) was noted in 88% (36/41) of non-splenectomised and 79% (33/42) of splenectomised patients given romiplostim compared with 14% (three of 21) of non-splenectomised and no splenectomised patients given placebo (p<0.0001). Patients given romiplostim achieved platelet counts of 50x10(9)/L or more on a mean of 13.8 (SE 0.9) weeks (mean 12.3 [1.2] weeks in splenectomised group vs 15.2 [1.2] weeks in non-splenectomised group) compared with 0.8 (0.4) weeks for those given placebo (0.2 [0.1] weeks vs 1.3 [0.8] weeks). 87% (20/23) of patients given romiplostim (12/12 splenectomised and eight of 11 non-splenectomised patients) reduced or discontinued concurrent therapy compared with 38% (six of 16) of those given placebo (one of six splenectomised and five of ten non-splenectomised patients). Adverse events were much the same in patients given romiplostim and placebo. No antibodies against romiplostim or thrombopoietin were detected. INTERPRETATION: Romiplostim was well tolerated, and increased and maintained platelet counts in splenectomised and non-splenectomised patients with ITP. Many patients were able to reduce or discontinue other ITP medications. Stimulation of platelet production by romiplostim may provide a new therapeutic option for patients with ITP.

AMG 531, a thrombopoiesis-stimulating protein, for chronic ITP.

BACKGROUND: Most current treatments for chronic immune thrombocytopenic purpura (ITP) act by decreasing platelet destruction. In a phase 1-2 study, we administered a thrombopoiesis-stimulating protein, AMG 531, to patients with ITP. METHODS: In phase 1, 24 patients who had received at least one treatment for ITP were assigned to escalating-dose cohorts of 4 patients each and given two identical doses of AMG 531 (0.2 to 10 microg per kilogram of body weight). In phase 2, 21 patients were randomly assigned to receive six weekly subcutaneous injections of AMG 531 (1, 3, or 6 microg per kilogram) or placebo. The primary objective was to assess the safety of AMG 531; the secondary objective was to evaluate platelet counts during and after treatment. RESULTS: No major adverse events that could be attributed directly to AMG 531 occurred during the treatment period; 4 of 41 patients had transient post-treatment worsening of thrombocytopenia. In phase 1, a platelet count that was within the targeted range (50,000 to 450,000 per cubic millimeter) and at least twice the baseline count was achieved in 4 of 12 patients given 3, 6, or 10 mug of AMG 531 per kilogram. Overall, a platelet count of at least 50,000 per cubic millimeter was achieved in 7 of 12 patients, including 3 with counts exceeding 450,000 per cubic millimeter. Increases in the platelet count were dose-dependent; mean peak counts were 163,000, 309,000, and 746,000 per cubic millimeter with 3, 6, and 10 microg of AMG 531 per kilogram [corrected], respectively. In phase 2, the targeted platelet range was achieved in 10 of 16 patients treated with 1 or 3 mug of AMG 531 per kilogram per week for 6 weeks. Mean peak counts were 135,000, 241,000, and 81,000 per cubic millimeter in the groups that received the 1-mug dose, the 3-mug dose, and placebo, respectively. CONCLUSIONS: AMG 531 caused no major adverse events and increased platelet counts in patients with ITP. (ClinicalTrials.gov number, NCT00111475 [ClinicalTrials.gov].).

High resolution remote sensing of densely urbanised regions: a case study of Hong Kong.

Data on the urban environment such as climate or air quality is usually collected at a few point monitoring stations distributed over a city. However, the synoptic viewpoint of satellites where a whole city is visible on a single image permits the collection of spatially comprehensive data at city-wide scale. In spite of rapid developments in remote sensing systems, deficiencies in image resolution and algorithm development still exist for applications such as air quality monitoring and urban heat island analysis. This paper describes state-of-the-art techniques for enhancing and maximising the spatial detail available from satellite images, and demonstrates their applications to the densely urbanised environment of Hong Kong. An Emissivity Modulation technique for spatial enhancement of thermal satellite images permits modelling of urban microclimate in combination with other urban structural parameters at local scale. For air quality monitoring, a Minimum Reflectance Technique (MRT) has been developed for MODIS 500 m images. The techniques described can promote the routine utilization of remotely sensed images for environmental monitoring in cities of the 21(st) century.

Modeling of Aerosol Vertical Profiles Using GIS and Remote Sensing.

The use of Geographic Information Systems (GIS) and Remote Sensing (RS) by climatologists, environmentalists and urban planners for three dimensional modeling and visualization of the landscape is well established. However no previous study has implemented these techniques for 3D modeling of atmospheric aerosols because air quality data is traditionally measured at ground points, or from satellite images, with no vertical dimension. This study presents a prototype for modeling and visualizing aerosol vertical profiles over a 3D urban landscape in Hong Kong. The method uses a newly developed technique for the derivation of aerosol vertical profiles from AERONET sunphotometer measurements and surface visibility data, and links these to a 3D urban model. This permits automated modeling and visualization of aerosol concentrations at different atmospheric levels over the urban landscape in near-real time. Since the GIS platform permits presentation of the aerosol vertical distribution in 3D, it can be related to the built environment of the city. Examples are given of the applications of the model, including diagnosis of the relative contribution of vehicle emissions to pollution levels in the city, based on increased near-surface concentrations around weekday rush-hour times. The ability to model changes in air quality and visibility from ground level to the top of tall buildings is also demonstrated, and this has implications for energy use and environmental policies for the tall mega-cities of the future.

Impact of chronic Immune Thrombocytopenic Purpura (ITP) on health-related quality of life: a conceptual model starting with the patient perspective.

BACKGROUND: Immune thrombocytopenic purpura (ITP), a condition characterized by autoimmune-mediated platelet destruction and suboptimal platelet production, is associated with symptoms such as bruising, epistaxis, menorrhagia, mucosal bleeding from the gastrointestinal and urinary tracts and, rarely central nervous system bleeding. The aim of this research is to develop a conceptual model to describe the impact of ITP and its treatment on patients' health-related quality of life (HRQoL). METHODS: A literature search and focus groups with adult ITP patients were conducted to identify areas of HRQoL affected by ITP. Published literature was reviewed to identify key HRQoL issues and existing questionnaires used to assess HRQoL. Focus group transcripts were reviewed, and common themes were extracted by grouping conceptual categories that described the impact on HRQoL. RESULTS: The literature synthesis and themes from the focus group data suggest that decreased platelet counts, disease symptoms, and treatment side effects influence multiple domains of HRQoL for ITP patients. Key areas affected by ITP and its treatments include emotional and functional health, work life, social and leisure activities, and reproductive health. CONCLUSION: ITP affects various areas of HRQoL. This conceptual model will help inform the evaluation of therapeutic strategies for ITP.

Fine Resolution Air Quality Monitoring from a Small Satellite: CHRIS/PROBA.

Current remote sensing techniques fail to address the task of air quality monitoring over complex regions where multiple pollution sources produce high spatial variability. This is due to a lack of suitable satellite-sensor combinations and appropriate aerosol optical thickness (AOT) retrieval algorithms. The new generation of small satellites, with their lower costs and greater flexibility has the potential to address this problem, with customised platform-sensor combinations dedicated to monitoring single complex regions or mega-cities. This paper demonstrates the ability of the European Space Agency's small satellite sensor CHRIS/PROBA to provide reliable AOT estimates at a spatially detailed level over Hong Kong, using a modified version of the dense dark vegetation (DDV) algorithm devised for MODIS. Since CHRIS has no middle-IR band such as the MODIS 2,100 nm band which is transparent to fine aerosols, the longest waveband of CHRIS, the 1,019 nm band was used to approximate surface reflectance, by the subtraction of an offset derived from synchronous field reflectance spectra. Aerosol reflectance in the blue and red bands was then obtained from the strong empirical relationship observed between the CHRIS 1,019 nm, and the blue and red bands respectively. AOT retrievals for three different dates were shown to be reliable, when compared with AERONET and Microtops II sunphotometers, and a Lidar, as well as air quality data at ground stations. The AOT images exhibited considerable spatial variability over the 11 x 11km image area and were able to indicate both local and long distance sources.

Pharmacodynamics and pharmacokinetics of AMG 531, a thrombopoiesis-stimulating peptibody, in healthy Japanese subjects: a randomized, placebo-controlled study.

AMG 531 is a novel thrombopoiesis-stimulating peptibody being investigated for the treatment of chronic immune thrombocytopenic purpura. This double-blind, phase I study evaluated the safety, pharmacodynamics, and pharmacokinetics of AMG 531 in healthy Japanese men. Thirty subjects were randomly assigned 4:1 (AMG 531/placebo) to receive 1 dose of AMG 531 (0.3, 1, or 2 microg/kg) or placebo by subcutaneous injection; subjects were evaluated for 6 weeks. AMG 531 was generally well tolerated, with adverse events similar to placebo. Treatment-related adverse events (headache, "feeling hot," malaise) were reported for 5 of 24 AMG 531-treated subjects. Platelets generated after exposure to AMG 531 functioned normally. Four of 8 subjects receiving 1 microg/kg and 7 of 8 receiving 2 microg/kg had platelet count increases > or =1.5-fold over baseline, an effect similar to that seen in non-Japanese subjects. Serum AMG 531 concentrations were below the lower limit of quantification in all but 2 subjects receiving 2 microg/kg.

A disease-specific measure of health-related quality of life in adults with chronic immune thrombocytopenic purpura: psychometric testing in an open-label clinical trial.

BACKGROUND: The Immune Thrombocytopenic Purpura Patient Assessment Questionnaire (ITP-PAQ) was developed to assess disease-specific quality of life (QoL) in adults with ITP. It is a 44-item questionnaire that includes scales for physical health (symptoms, fatigue/sleep, bother, and activity), emotional health (psychological and fear), overall QoL, social activity, women's reproductive health, and work. A previous study reported preliminary evidence of its reliability and validity. OBJECTIVES: The present study was conducted to ascertain the responsiveness (ability to detect a clinically important treatment effect), reliability, and validity of the ITP-PAQ and to corroborate the earlier findings. The women's reproductive health scale was evaluated for psychometric evidence of the existence of separate menstrual symptoms and fertility subscales. METHODS: The ITP-PAQ was evaluated in the context of an ongoing open-label extension study assessing the tolerability and durability of increases in the platelet count with AMG 531 (a thrombopoiesis peptibody that increases platelet production by targeting the thrombopoietin receptor) administered by subcutaneous injection once weekly in adult patients with ITP It was self-administered at baseline and at weeks 4, 12, and 24. The responsiveness of the questionnaire was evaluated by calculating and comparing the change scores of patients who showed clinical improvement-categorized as platelet responders (those with a platelet count > or =50 x 10(9) cells/L and a doubling of baseline values at week 24) and durable platelet responders (those with a platelet count > or =50 x 10(9) cells/L and a doubling of baseline values on > or =6 occasions during weeks 17-24)-with the change scores of patients wh did not show clinical improvement. The reliability (internal consistency and test-retest) and validity (convergent, discriminant, and known groups) of the questionnaire were also evaluated. Validity was examined in terms of correlations between the ITP-PAQ and the 36-item Short-Form Health Survey (SF-36), a generic measure of health-related QoL. RESULTS: Thirty-four patients completed the ITP-PAQ. Most of the scales were found capable of detecting clinically important treatment effects, with the scales for symptoms, fatigue/sleep, bother, and activity being particularly responsive. All scales were found to have internal consistency reliability (Cronbach's alpha, 0.700-0.950), with the exceptions of the menstrual symptoms subscale (0.988 and 0.959 at weeks 12 and 24, respectively) and the work scale (0.691 at week 24). Test-retest reliability was acceptable (intraclass correlation coefficient, 0.725-0.867), with the exceptions of the scales for symptoms (0.677) and women's reproductive health (0.592) and the fertility subscale (0.171). Construct validity was supported by correlations between specific ITP-PAQ and SF-36 scales, with the exceptions of the menstrual symptoms and fertility subscales. Discriminant validity was reported for the symptoms, fatigue/sleep, bother, and activity scales. Durable platelet responders had significantly better scores than nonresponders on the symptoms (P = 0.022), bother (P = 0.008), psychological (P = 0.033), and overall QoL scales (P = 0.032). Compared with those who had undergone splenectomy, patients without splenectomy had significantly higher scores on the women's reproductive health scale (P = 0.03). CONCLUSIONS: The results of this analysis indicate that the ITP-PAQ has acceptable responsiveness, reliability, and validity. Further study of the minimal clinically important difference in ITP-PAQ scale scores is needed.

A disease-specific measure of health-related quality of life for use in adults with immune thrombocytopenic purpura: its development and validation.

BACKGROUND: No validated disease-specific measures are available to assess health-related quality of life (HRQoL) in adult subjects with immune thrombocytopenic purpura (ITP). Therefore, we sought to develop and validate the ITP-Patient Assessment Questionnaire (ITP-PAQ) for adult subjects with ITP. METHODS: Information from literature reviews, focus groups with subjects, and clinicians were used to develop 50 ITP-PAQ items. Factor analyses were conducted to develop the scale structure and reduce the number of items. The final 44-item ITP-PAQ, which includes ten scales [Symptoms (S), Bother-Physical Health (B), Fatigue/Sleep (FT), Activity (A), Fear (FR), Psychological Health (PH), Work (W), Social Activity (SA), Women's Reproductive Health (RH), and Overall (QoL)], was self-administered to adult ITP subjects at baseline and 7-10 days later. Test-retest reliability, internal consistency reliability, construct and known groups validity of the final ITP-PAQ were evaluated. RESULTS: Seventy-three subjects with ITP completed the questionnaire twice. Test-retest reliability, as measured by the intra-class correlation, ranged from 0.52-0.90. Internal consistency reliability was demonstrated with Cronbach's alpha for all scales above the acceptable level of 0.70 (range: 0.71-0.92), except for RH (0.66). Construct validity, assessed by correlating ITP-PAQ scales with established measures (Short Form-36 v.1, SF-36 and Center for Epidemiologic Studies Depression Scale, CES-D), was demonstrated through moderate correlations between the ITP-PAQ SA and SF-36 Social Function scales (r = 0.67), and between ITP-PAQ PH and SF-36 Mental Health Scales (r = 0.63). Moderate to strong inter-scale correlations were reported between ITP-PAQ scales and the CES-D, except for the RH scale. Known groups validity was evaluated by comparing mean scores for groups that differed clinically. Statistically significant differences (p < 0.01) were observed when subjects were categorized by treatment status [S, FT, B, A, PH, and QoL, perceived effectiveness of ITP treatment [S], and time elapsed since ITP diagnosis [PH]. CONCLUSION: Results provide preliminary evidence of the reliability and validity of the ITP-PAQ in adult subjects with ITP. Further work should be conducted to assess the responsiveness and to estimate the minimal clinical important difference of the ITP-PAQ to more fully understand the impact of ITP and its treatments on HRQoL.