Both pulmonary and extra-pulmonary factors predict the development of disability in chronic obstructive pulmonary disease

BACKGROUND

Although chronic obstructive pulmonary disease (COPD) is a major cause of disability worldwide, its determinants remain poorly defined.

OBJECTIVE

We hypothesized that both pulmonary and extra-pulmonary factors would predict prospective disablement across a hierarchy of activities in persons with COPD.

METHODS

Six hundred and nine participants were studied at baseline (T0) and 2.5 years later (T1). The Valued Life Activities (VLA) scale quantified disability (10-point scale: 0 = no difficulty and 10 = unable to perform), defining disability as any activity newly rated 'unable to perform' at T1. Predictors included pulmonary (lung function, 6-minute walk distance and COPD severity score) and extra-pulmonary (quadriceps strength and lower extremity function) factors. Prospective disability risk was tested by separate logistic regression models for each predictor (baseline value and its change, T0-T1; odds ratios were scaled at 1 standard deviation per factor. Incident disability across a hierarchy of obligatory, committed and discretionary VLA subscales was compared.

RESULTS

Subjects manifested a 40% or greater increased odds of developing disability for each predictor (baseline and change over time). Disability in discretionary activities developed at a rate 2.2-times higher than observed in committed activities, which was in turn 2.5-times higher than the rate observed in obligatory activities (p < 0.05 for each level).

CONCLUSIONS

Disability is common in COPD. Both pulmonary and extra-pulmonary factors are important in predicting its development.

Disturbed sleep among COPD patients is longitudinally associated with mortality and adverse COPD outcomes

OBJECTIVE

To investigate the cross-sectional association between COPD severity and disturbed sleep and the longitudinal association between disturbed sleep and poor health outcomes.

METHODS

Ninety eight adults with spirometrically-confirmed COPD were recruited through population-based, random-digit telephone dialing. Sleep disturbance was evaluated using a 4-item scale assessing insomnia symptoms as: difficulty falling asleep, nocturnal awakening, morning tiredness, and sleep duration adequacy. COPD severity was quantified by: FEV(1) and COPD Severity Score, which incorporates COPD symptoms, requirement for COPD medications and oxygen, and hospital-based utilization. Subjects were assessed one year after baseline to determine longitudinal COPD exacerbations and emergency utilization and were followed for a median 2.4 years to assess all-cause mortality.

RESULTS

Sleep disturbance was cross-sectionally associated with cough, dyspnea, and COPD Severity Score, but not FEV(1). In multivariable logistic regression, controlling for sociodemographics and body-mass index, sleep disturbance longitudinally predicted both incident COPD exacerbations (OR=4.7; p=0.018) and respiratory-related emergency utilization (OR=11.5; p=0.004). In Cox proportional hazards analysis, controlling for the same covariates, sleep disturbance predicted poorer survival (HR=5.0; p=0.013). For all outcomes, these relationships persisted after also controlling for baseline FEV(1) and COPD Severity Score.

CONCLUSIONS

Disturbed sleep is cross-sectionally associated with worse COPD and is longitudinally predictive of COPD exacerbations, emergency health care utilization, and mortality.

A patient on RIPE therapy presenting with recurrent isoniazid-associated pleural effusions: a case report

INTRODUCTION

The clinical scenario of a new or worsening pleural effusion following the initiation of antituberculous therapy has been classically referred to as a 'paradoxical' pleural response, presumably explained by an immunological rebound phenomenon. Emerging evidence suggests that there also may be a role for a lupus-related reaction in the pathophysiology of this disorder.

CASE PRESENTATION

An 84-year-old Asian man treated with isoniazid, along with rifampin, pyrazinamide and ethambutol for suspected extrapulmonary tuberculosis, presented with a recurrent pleural effusion, his third episode since the initiation of this therapy. The first effusion occurred one month after the start of treatment, without any prior evidence of pulmonary tuberculosis involvement. Follow-up testing, including thoracoscopic pleural biopsies, never confirmed tuberculosis infection. Further evaluation yielded serological evidence suggesting drug-induced lupus. No effusions recurred following the discontinuation of isoniazid, although other antituberculosis medications were continued.

CONCLUSION

The immunological rebound construct is inconsistent with the evolution of this case, which indicates rather that drug-induced lupus may explain at least some cases of new pleural effusions following the initiation of isoniazid.

Survival following lung transplantation for silicosis and other occupational lung diseases

BACKGROUND

Information is scant assessing outcomes in lung transplantation (LT) in advanced occupational lung diseases (OLD).

AIMS

To analyse survival after LT for OLD.

METHODS

Using data from the US Organ Procurement and Transplantation Network Registry (OPTN-R), we identified subjects aged ≥ 18 years transplanted for OLD from 2005 to 2010. OPTN-R selected referents of corresponding age, sex and body mass index (BMI) who underwent LT for other diagnoses were also identified. Post-LT survival time was estimated with Cox proportional hazard models. Baseline age, BMI, forced expiratory volume in 1 s, creatinine, lung allocation score, donor age, donor lung ischaemic time and transplant type (single versus bilateral) were included as covariates. Time-dependent covariates were used to model differences in relative risk over time.

RESULTS

Thirty-seven males underwent LT for silicosis (n = 19) or other OLD (n = 18) during the analytic period (0.5% of all LTs). For non-silicotic OLD, 6-month and 1- and 3-year survival estimates were 66, 55 and 55%, compared with the silicotic group (86, 86 and 76%) and referent group (89, 84 and 67%). During the first year post-transplant, those with OLD (silicosis and others combined) manifested an overall 2-fold increased mortality risk [hazard ratio (HR) 2.3, 95% CI 1.3-4.4; P < 0.05] compared to referents. In stratified analysis, this increased risk of death was restricted to those with non-silicotic OLD (HR 3.1, 95% CI 1.5-6.6; P < 0.01). Poorer survival was limited to the first year post-LT.

CONCLUSIONS

Subjects undergoing LT for OLD other than silicosis may be at increased risk of death in the first year post-transplantation.

5-oxoprolinemia causing elevated anion gap metabolic acidosis in the setting of acetaminophen use

BACKGROUND

Anion gap metabolic acidosis is typically encountered in the emergency department (ED) setting as the result of shock, other endogenous metabolic derangements, or from exogenous toxicants. The differential diagnosis for toxicant-related acidosis (exemplified by common mnemonics) emphasizes acute overdose.

CASE REPORT

The case we present manifested an anion gap (AG) metabolic acidosis due to a chronic intoxication: acetaminophen (APAP) overuse over a period of weeks. Lactic acidemia did not account for the AG. In this case, chronic APAP overuse, combined with decreased caloric intake and weight loss, was associated with excess 5-oxoproline (pyroglutamic acid), an organic acid accounting for the AG metabolic acidosis. Overproduction of 5-oxoproline is attributed to depleted glutathione stores, leading to perturbation in the γ-glutamyl cycle. The patient was treated with supportive care and with N-acetylcysteine (NAC). By repleting glutathione, NAC may facilitate the resolution of excess 5-oxoproline.

CONCLUSIONS

The ED differential diagnosis of AG metabolic acidosis in chronic APAP overuse, especially with concomitant nutritional compromise, should include 5-oxoprolinemia.

The impact of pretransplant mechanical ventilation on short- and long-term survival after lung transplantation

Lung transplantation in mechanically ventilated (MV) patients has been associated with decreased posttransplant survival. Under the Lung Allocation Score (LAS) system, patients at greatest risk of death on the waiting list, particularly those requiring MV, are prioritized for lung allocation. We evaluated whether pretransplant MV is associated with poorer posttransplant survival in the LAS era. Using a national registry, we analyzed all adults undergoing lung transplantation in the United States from 2005 to 2010. Propensity scoring identified nonventilated matched referents for 419 subjects requiring MV at the time of transplantation. Survival was evaluated using Kaplan-Meier methods. Risk of death was estimated by hazard ratios employing time-dependent covariates. We found that pretransplant MV was associated with decreased overall survival after lung transplantation. In the first 6 months posttransplant, ventilated subjects had a twofold higher risk of death compared to nonventilated subjects. However, after 6 months posttransplant, survival did not differ by MV status. We also found that pretransplant MV was not associated with decreased survival in noncystic fibrosis obstructive lung diseases. These results suggest that under the LAS, pretransplant MV is associated with poorer short-term survival posttransplant. Notably, the increased risk of death appears to be strongest the early posttransplant period and limited to certain pretransplant diagnoses.

Occupation and COPD: a brief review

BACKGROUND AND AIMS

This review summarizes the scientific literature relevant to occupational risk factors for chronic obstructive pulmonary disease (COPD).

MATERIAL AND METHODS

This review emphasizes recent work in the field, while placing this in the context of two previous systematic reviews of the subject.

RESULTS

Both the earlier summaries of the literature estimated that the population attributable risk percent (PAR%) of COPD linked to occupational exposures is approximately 15%. More recent studies also strongly support the association between workplace exposures and COPD. Among never smokers, the PAR% for work-related factors may approach 40%. Emerging data also indicate that occupational exposures, at a minimum, are additive to smoking-associated risk of COPD.

CONCLUSIONS

The PAR% for work-related COPD is at least 15%. Scientific significance. The consistency, strength, and plausibility of these data support a causal relationship between occupational exposures and COPD.

Fungal chitin from asthma-associated home environments induces eosinophilic lung infiltration

Development of asthma and allergic inflammation involves innate immunity, but the environmental contributions remain incompletely defined. Analysis of dust collected from the homes of asthmatic individuals revealed that the polysaccharide chitin is environmentally widespread and associated with β-glucans, possibly from ubiquitous fungi. Cell wall preparations of Aspergillus isolated from house dust induced robust recruitment of eosinophils into mouse lung, an effect that was attenuated by enzymatic degradation of cell wall chitin and β-glucans. Mice expressing constitutively active acidic mammalian chitinase in the lungs demonstrated a significant reduction in eosinophil infiltration after fungal challenge. Conversely, chitinase inhibition prolonged the duration of tissue eosinophilia. Thus, fungal chitin derived from home environments associated with asthma induces eosinophilic allergic inflammation in the lung, and mammalian chitinases, including acidic mammalian chitinase, limit this process.

Cutaneous nerve transection for the management of intractable upper extremity pain caused by invasive squamous cell carcinoma

A recurrent clinical dilemma in the management of patients with painful metastatic lesions is achieving a balance between effective analgesic therapies versus intolerable side effects, in particular altered mental status. We present the case of an immunosuppressed patient post-lung transplant who was suffering from intractable pain caused by widely metastatic squamous cell carcinoma. The patient's progressive, excruciating neuropathic pain was localized to the area of the left wrist and forearm. Additionally, the patient complained of moderate pain at sites of tumor involvement on her right arm and scalp. Attempts to adequately manage her left upper extremity pain included a combination of pharmacologic treatments intended to treat neuropathic pain (gabapentin, SNRI, ketamine, opioids) and focused regional analgesia (infraclavicular infusion of local anesthetic). However, the patient developed intolerable side effects including altered mental status and delirium associated with the systemic agents and suboptimal control with the infraclavicular infusion. Given that the most severe pain was well localized, we undertook a diagnostic block of the cutaneous nerves of the left forearm. As this intervention significantly reduced her pain, we subsequently performed neurectomies to the left superficial radial nerve, lateral cutaneous nerve of the forearm and the posterior cutaneous nerve of the forearm. This resulted in immediate and continued relief of her left upper extremity pain without an altered mental status. Residual focal pain from lesions over her right arm and scalp was successfully managed with daily topical applications of lidocaine and capsaicin cream. Successful pain control continued until the patient's death five months later.

Alpha-1-antitrypsin deficient man presenting with lung function decline associated with dust exposure: a case report

Introduction

People with α₁-antitrypsin deficiency are at increased risk for the development of chronic obstructive pulmonary disease. Previous retrospective epidemiologic studies have found that exposure to occupational dust among those with α₁-antitrypsin deficiency is a risk factor at the group level for poorer lung function, but on an individual clinical basis, a causal attribution can be difficult to establish.

Case presentation

We describe the case of a 68-year-old Caucasian man with a 25 pack-year smoking history who presented with new-onset dyspnea on exertion in the setting of workplace dust exposure. During his evaluation, he was found to have α₁-antitrypsin deficiency with evidence of development of pulmonary emphysema. Workplace spirometric monitoring over 10 years of surveillance for an on-the-job respirator fit program demonstrated a sharp downward slope in forced expiratory volume in one second, or FEV₁, during his periods of most significant dust exposure, which was attenuated after discontinuation of his workplace exposure.

Conclusion

Patients with α₁-antitrypsin disease should be assessed for occupational exposures and closely monitored for work-accelerated progression of lung function decline. More generally, this case report supports the biological plausibility of occupationally associated chronic obstructive pulmonary disease, underscoring that work-associated pulmonary disease can be multi-factorial.

Matrix metalloproteinase-9 predicts pulmonary status declines in α1-antitrypsin deficiency

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) may be important in the progression of emphysema, but there have been few longitudinal clinical studies of MMP-9 including pulmonary status and COPD exacerbation outcomes.

METHODS

We utilized data from the placebo arm (n=126) of a clinical trial of patients with alpha1-antitrypsin deficiency (AATD) and emphysema to examine the links between plasma MMP-9 levels, pulmonary status, and COPD exacerbations over a one year observation period. Pulmonary function, computed tomography lung density, incremental shuttle walk test (ISWT), and COPD exacerbations were assessed at regular intervals over 12 months. Prospective analyses used generalized estimating equations to incorporate repeated longitudinal measurements of MMP-9 and all endpoints, controlling for age, gender, race-ethnicity, leukocyte count, and tobacco history. A secondary analysis also incorporated highly-sensitive C-reactive protein levels in predictive models.

RESULTS

At baseline, higher plasma MMP-9 levels were cross-sectionally associated with lower FEV1 (p=0.03), FVC (p<0.001), carbon monoxide transfer factor (p=0.03), resting oxygen saturation (p=0.02), and ISWT distance walked (p=0.02) but were not associated with radiographic lung density or total lung capacity (TLC). In longitudinal analyses, MMP-9 predicted a further decline in transfer factor (p=0.04) and oxygen saturation (p<0.001). MMP-9 also predicted worsening lung density (p=0.003), increasing TLC (p=0.02), and more frequent COPD exacerbations over follow-up (p=0.003). Controlling additionally for hs-CRP levels did not substantively change the longitudinal associations between MMP-9 and these outcomes.

CONCLUSIONS

Increased plasma MMP-9 levels generally predicted pulmonary status declines, including worsening transfer factor and lung density as well as greater COPD exacerbations in AATD-associated emphysema.

Comparison of cardiac and pulmonary-specific quality-of-life measures in pulmonary arterial hypertension

Studies systematically comparing the performance of health-related quality-of-life (HRQoL) instruments in pulmonary arterial hypertension (PAH) are lacking. We sought to address this by comparing cardiac and respiratory-specific measures of HRQoL in PAH. We prospectively assessed HRQoL in 128 patients with catheterisation-confirmed PAH at baseline and at 6, 12 and post-24 month follow-up visits. Cardiac-specific HRQoL was assessed using the Minnesota Living with Heart Failure Questionnaire (LHFQ); respiratory-specific HRQoL was assessed using the Airways Questionnaire 20 (AQ20); and general health status was assessed using the 36-item Short Form physical component summary (SF-36 PCS). The LHFQ and AQ20 were highly intercorrelated. Both demonstrated strong internal consistency and converged with the SF-36 PCS. Both discriminated patients based on World Health Organization (WHO) functional class, 6-min walking distance (6MWD) and Borg dyspnoea index (BDI), with the exception of a potential floor effect associated with low 6MWD. The LHFQ was more responsive than the AQ20 to changes over time in WHO functional class, 6MWD and BDI. In multivariate analyses, the LHFQ and AQ20 were each longitudinal predictors of general health status, independent of functional class, 6MWD and BDI. In conclusion, both cardiac-specific and respiratory-specific measures appropriately assess HRQoL in most patients with PAH. Overall, the LHFQ demonstrates stronger performance characteristics than the AQ20.

Evaluating quality of life in patients with asthma and rhinitis: English adaptation of the rhinasthma questionnaire

BACKGROUND

Separate health-related quality of life (HRQL) instruments exist for asthma and rhinitis. The Rhinasthma questionnaire, originally developed in Italian, is a unique measure designed for use where both conditions coexist.

OBJECTIVE

We sought to assess the performance and validity of a new adaptation of the Rhinasthma questionnaire for use in English-speaking populations.

METHODS

We analyzed cross-sectional data from an ongoing study of adults with asthma and rhinitis (n = 450), asthma alone (n = 75), or rhinitis alone (n = 20). Subjects were administered an English translation of the original 30-item Rhinasthma questionnaire. Health status measures simultaneously assessed include the Short Form (SF)-12, EuroQol (EQ)-5D, and Marks Asthma Quality-of-Life.

RESULTS

Variable cluster analysis of the original 30-item instrument identified 5 discrete item clusters corresponding to the following domains: nasal (5 items), eye (4 items), respiratory (5 items), activity restriction (9 items), and treatment burden (5 items). Two other items were removed because of poor item-cluster correlations. Subjects with concomitant asthma and rhinitis had greater HRQL impairment, as measured by the Rhinasthma, than subjects with either asthma or rhinitis alone. The Rhinasthma correlated significantly (P < .05) with the SF-12, EQ-5D, and Marks Asthma Quality-of-Life in the anticipated direction consistent with the underlying constructs. In multiple logistic regression, poorer Rhinasthma HRQL was associated with significantly (P < .05) increased odds of both asthma- and rhinitis-related disability even after taking into account physical health status as measured by the SF-12.

CONCLUSION

The 28-item English adaptation of Rhinasthma performs well in assessing HRQL in patients with asthma, rhinitis, or both conditions combined.

Onset of depressive symptoms among adults with asthma: results from a longitudinal observational cohort

AIMS

Individuals with asthma may be at increased risk of depression, but few studies have identified precursors to the onset of depression. The study goal was to identify risk factors for depression onset among a community-based sample of adults with asthma.

METHODS

Data were obtained from three telephone interviews conducted at 2-yearly intervals on a longitudinal cohort of adults with asthma (n=439). The Center for Epidemiologic Studies Depression scale (CESD) was used to measure depressive symptoms. Multiple regression analyses tested associations of sociodemographic and health-related variables with depression prevalence (cross-sectional analyses) and incident depression (longitudinal analyses).

RESULTS

15% of subjects were classified as "depressed" (CESD> or =23) at each interview. Individuals depressed at baseline were more likely to drop out (OR=1.76 [95% CI 1.05, 2.96]). Low perceived control of asthma (measured with the Perceived Control of Asthma Questionnaire [PCAQ]) exhibited the most consistent association with depression. Lower PCAQ was cross-sectionally associated with depression (OR=0.51 per 0.5 SD difference in PCAQ [0.35, 0.75]). Onset of depression was noted in 38 individuals. Decrease in perceived control at follow-up was associated with depression onset (OR=7.47 [2.15, 26.01]).

CONCLUSIONS

Low perceived control of asthma predicted depression onset among adults with asthma. This risk factor may respond to self-management education.

Socioeconomic status, race and COPD health outcomes

BACKGROUND

Although chronic obstructive pulmonary disease (COPD) is a common cause of death and disability, little is known about the effects of socioeconomic status (SES) and race-ethnicity on health outcomes.

METHODS

The aim of this study is to determine the independent impacts of SES and race-ethnicity on COPD severity status, functional limitations and acute exacerbations of COPD among patients with access to healthcare. Data were used from the Function, Living, Outcomes and Work cohort study of 1202 Kaiser Permanente Northern California Medical Care Plan members with COPD.

RESULTS

Lower educational attainment and household income were consistently related to greater disease severity, poorer lung function and greater physical functional limitations in cross-sectional analysis. Black race was associated with greater COPD severity, but these differences were no longer apparent after controlling for SES variables and other covariates (comorbidities, smoking, body mass index and occupational exposures). Lower education and lower income were independently related to a greater prospective risk of acute COPD exacerbation (HR 1.5; 95% CI 1.01 to 2.1; and HR 2.1; 95% CI 1.4 to 3.4, respectively).

CONCLUSION

Low SES is a risk factor for a broad array of adverse COPD health outcomes. Clinicians and disease management programs should consider SES as a key patient-level marker of risk for poor outcomes.

Development of disability in chronic obstructive pulmonary disease: beyond lung function

BACKGROUND

COPD is a major cause of disability, but little is known about how disability develops in this condition.

METHODS

The authors analysed data from the Function, Living, Outcomes and Work (FLOW) Study which enrolled 1202 Kaiser Permanente Northern California members with COPD at baseline and re-evaluated 1051 subjects at 2-year follow-up. The authors tested the specific hypothesis that the development of specific non-respiratory impairments (abnormal body composition and muscle strength) and functional limitations (decreased lower extremity function, poor balance, mobility-related dyspnoea, reduced exercise performance and decreased cognitive function) will determine the risk of disability in COPD, after controlling for respiratory impairment (FEV(1) and oxygen saturation). The Valued Life Activities Scale was used to assess disability in terms of a broad range of daily activities. The primary disability outcome measure was defined as an increase in the proportion of activities that cannot be performed of 3.3% or greater from baseline to 2-year follow-up (the estimated minimal important difference). Multivariable logistic regression was used for analysis.

RESULTS

Respiratory impairment measures were related to an increased prospective risk of disability (multivariate OR 1.75; 95% CI 1.26 to 2.44 for 1 litre decrement of FEV(1) and OR 1.57 per 5% decrement in oxygen saturation; 95% CI 1.13 to 2.18). Non-respiratory impairment (body composition and lower extremity muscle strength) and functional limitations (lower extremity function, exercise performance, and mobility-related dyspnoea) were all associated with an increased longitudinal risk of disability after controlling for respiratory impairment (p<0.05 in all cases). Non-respiratory impairment and functional limitations were predictive of prospective disability, above-and-beyond sociodemographic characteristics, smoking status and respiratory impairment (area under the receiver operating characteristic curve increased from 0.65 to 0.75; p<0.001).

CONCLUSIONS

Development of non-respiratory impairment and functional limitations, which reflect the systemic nature of COPD, appear to be critical determinants of disablement. Prevention and treatment of disability require a comprehensive approach to the COPD patient.

COPD and cognitive impairment: the role of hypoxemia and oxygen therapy

Background:

Several studies have shown an association between chronic obstructive pulmonary disease (COPD) and cognitive impairment. These studies have been limited by methodological issues such as diagnostic uncertainty, cross-sectional design, small sample size, or lack of appropriate referent group. This study aimed to elucidate the association between COPD and the risk of cognitive impairment compared to referent subjects without COPD. In patients with established COPD, we evaluated the impact of disease severity and impairment of respiratory physiology on cognitive impairment and the potential mitigating role of oxygen therapy.

Methods:

We used the Function, Living, Outcomes and Work (FLOW) cohort study of adults with COPD (n = 1202) and referent subjects matched by age, sex, and race (n = 302) to study the potential risk factors for cognitive impairment among subjects with COPD. Cognitive impairment was defined as a Mini-Mental State Exam score of <24 points. Disease severity was using Forced Expiratory Volume in one second (FEV₁); the validated COPD Severity Score; and the BMI (Body Mass Index), Obstruction, Dyspnea, Exercise Capacity (BODE) Index. Multivariable analysis was used to control for confounding by age, sex, race, educational attainment, and cigarette smoking.

Results:

COPD was associated with a substantive risk of cognitive impairment compared to referent subjects (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.043–6.64). Among COPD patients, none of the COPD severity measures were associated with the risk of cognitive impairment (P > 0.20 in all cases). Low baseline oxygen saturation was related to increased risk of cognitive impairment (OR for oxygen saturation ≤88% (OR 5.45; 95% CI 1.014–29.2; P = 0.048). Conversely, regular use of supplemental oxygen therapy decreased the risk for cognitive impairment (OR 0.14; 95% CI 0.07–0.27; P < 0.0001).

Conclusion:

COPD is a major risk factor for cognitive impairment. Among patients with COPD, hypoxemia is a major contributor and regular use of home oxygen is protective. Health care providers should consider screening their COPD patients for cognitive impairment.

Functional recovery following musculoskeletal injury in hospital workers

BACKGROUND

Hospital workers are at high risk of work-related musculoskeletal disorders (WRMSDs), but outcomes following such injuries have not been well studied longitudinally.

AIMS

To ascertain functional recovery in hospital workers following incident WRMSDs and identify predictors of functional status.

METHODS

Cases (incident WRMSD) and matched referents from two hospitals were studied at baseline and at 2 year follow-up for health status [SF-12 physical component summary (PCS)], lost workdays, self-rated work effectiveness and work status change (job change or work cessation). Predictors included WRMSD and baseline demographics, socio-economic status (SES), job-related strain and effort-reward imbalance. Logistic regression analysis tested longitudinal predictors of adverse functional status.

RESULTS

The WRMSD-associated risk of poor (lowest quartile) PCS was attenuated from a baseline odds ratio (OR) of 5.2 [95% confidence interval (CI) 3.5-7.5] to a follow-up OR of 1.5 (95% CI 1.0-2.3) and was reduced further in multivariate modelling (OR = 1.4; 95% CI 0.9-2.2). At follow-up, WRMSD status did not predict significantly increased likelihood of lost workdays, decreased effectiveness or work status change. In multivariate modelling, lowest quintile SES predicted poor PCS (OR = 2.0; 95% CI 1.0-4.0) and work status change (OR = 2.5; 95% CI 1.1-5.8). High combined baseline job strain/effort-reward imbalance predicted poor PCS (OR = 1.7; 95% CI 1.1-2.7) and reduced work effectiveness (OR = 2.6; 95% CI 1.6-4.2) at follow-up.

CONCLUSIONS

Baseline functional deficits associated with incident WRMSDs were largely resolved by 2 year follow-up. Nonetheless, lower SES and higher combined job strain/effort-reward imbalance predicted adverse outcomes, controlling for WRMSDs.

Topical antacid therapy for capsaicin-induced dermal pain: a poison center telephone-directed study

PURPOSE

The study aimed to assess the effects of topical antacids for treatment of capsaicin-induced dermal pain after exposure to capsaicin containing hot peppers, personal protection sprays, or topical creams.

PROCEDURES

Participants of the study were California Poison Control System (CPCS) hotline callers 12 years or older with dermal pain from exposure to capsaicin-containing products or plants. Participants were instructed to apply a topical antacid and assessed for perceived pain (using a 0-10 scale) pre- and posttreatment. A positive response was defined as a sustained reduction of pain 33% or more within 30 minutes or achieving a pain score of 0 to 1.

MAIN FINDINGS

Of 93 eligible patients, 64 applied antacids and had outcome data available. Patients contacted the CPCS a median of 1 hour postexposure with a median initial pain score of 7.5/10. Thirty-six (56%) were exposed to unrefined (natural) peppers and 28 (44%) to refined capsaicin (eg, capsaicin-containing cream). Before calling the CPCS, 57 (89%) attempted at least one treatment. Forty-five (70%) reported positive response to antacid treatment as a 33% reduction in pain in 30 minutes (n = 17), a reduction in pain to a score of 0 to 1 (n = 3), or both (n = 25). A 33% reduction in pain within 30 minutes was associated with exposure to refined capsaicin (odds ratio, 3.37; 95% confidence interval, 0.98-11.66). Concomitant refined capsaicin exposure and early treatment (<1 hour of symptoms) was associated with even greater odds of response (odds ratio, 5.4; 95% confidence interval, 1.4-21.2).

CONCLUSION

Topical application of antacids for capsaicin-induced pain is effective, particularly in early treatment of exposure to refined capsaicin.

Supratherapeutic anticoagulation from low-molecular-weight heparin in lung transplant recipients

BACKGROUND

Venous thromboembolism (VTE) is common after lung transplantation. Enoxaparin is an approved therapy for VTE and anti-factor Xa level can be used to monitor enoxaparin activity. Some studies have demonstrated elevated anti-factor Xa levels are associated with an increased risk of hemorrhage. Having identified a high incidence of supratherapeutic anti-factor Xa levels in lung transplant recipients, we aimed to elucidate the relationship between enoxaparin dose and anti-factor Xa level in this patient population.

METHODS

We identified post-lung transplantation patients with VTE receiving therapeutic enoxaparin who had anti-factor Xa level measured. Standard enoxaparin dosing was defined as 0.9 to 1.1 mg/kg. After identifying a high incidence of supratherapeutic anti-factor Xa levels, we implemented "non-standard" dosing of 0.8 mg/kg. Multivariate linear regression analysis was used to examine the association between enoxaparin dose and anti-factor Xa level; age, body mass index (BMI) and creatinine clearance were included as covariates.

RESULTS

In the cohort, 18 patients received standard and 8 patients received non-standard enoxaparin dosing. Twelve of 18 patients (67%; 95% confidence interval [CI]: 43% to 91%) receiving standard dosing had supratherapeutic anti-factor Xa levels vs 0 of 8 patients (0%; 95% CI: 0% to 37%) receiving lower non-standard dosing (p = 0.002). Anti-factor Xa levels were significantly different between the two groups; the mean anti-factor Xa level was 1.3 IU/ml (95% CI: 1.06 to 1.53) in the standard group vs 0.79 IU/ml (95% CI: 0.67 to 0.91) in the non-standard group (p = 0.008). After controlling for covariates, for each 0.1-mg/kg increase in enoxaparin, the mean anti-factor Xa level increased by 0.18 IU/ml (95% CI: 0.05 to 0.31; p = 0.011; model r(2) = 0.53).

CONCLUSIONS

Standard dosing of enoxaparin in lung transplant recipients is associated with a high incidence of supratherapeutic anti-Xa levels. Further study will be required to correlate this finding with risk of hemorrhage.

An integrated model of environmental factors in adult asthma lung function and disease severity: a cross-sectional study

BACKGROUND

Diverse environmental exposures, studied separately, have been linked to health outcomes in adult asthma, but integrated multi-factorial effects have not been modeled. We sought to evaluate the contribution of combined social and physical environmental exposures to adult asthma lung function and disease severity.

METHODS

Data on 176 subjects with asthma and/or rhinitis were collected via telephone interviews for sociodemographic factors and asthma severity (scored on a 0-28 point range). Dust, indoor air quality, antigen-specific IgE antibodies, and lung function (percent predicted FEV1) were assessed through home visits. Neighborhood socioeconomic status, proximity to traffic, land use, and ambient air quality data were linked to the individual-level data via residential geocoding. Multiple linear regression separately tested the explanatory power of five groups of environmental factors for the outcomes, percent predicted FEV1 and asthma severity. Final models retained all variables statistically associated (p < 0.20) with each of the two outcomes.

RESULTS

Mean FEV1 was 85.0 +/- 18.6%; mean asthma severity score was 6.9 +/- 5.6. Of 29 variables screened, 13 were retained in the final model of FEV1 (R2 = 0.30; p < 0.001) and 15 for severity (R2 = 0.16; p < 0.001), including factors from each of the five groups. Adding FEV1 as an independent variable to the severity model further increased its explanatory power (R2 = 0.25).

CONCLUSIONS

Multivariate models covering a range of individual and environmental factors explained nearly a third of FEV1 variability and, taking into account lung function, one quarter of variability in asthma severity. These data support an integrated approach to modeling adult asthma outcomes, including both the physical and the social environment.

Influence of anxiety on health outcomes in COPD

BACKGROUND

Psychological functioning is an important determinant of health outcomes in chronic lung disease. To better define the role of anxiety in chronic obstructive pulmonary disease (COPD), a study was conducted of the inter-relations between anxiety and COPD in a large cohort of subjects with COPD and a matched control group.

METHODS

Data were used from the FLOW (Function, Living, Outcomes, and Work) cohort of patients with COPD (n=1202) and matched controls without COPD (n=302). Anxiety was measured using the Anxiety subscale of the Hospital Anxiety and Depression Scale.

RESULTS

COPD was associated with a greater risk of anxiety in multivariable analysis (OR 1.85; 95% CI 1.072 to 3.18). Among patients with COPD, anxiety was related to poorer health outcomes including worse submaximal exercise performance (less distance walked during the 6-min walk test: -66.3 feet for anxious vs non-anxious groups; 95% CI -127.3 to -5.36) and a greater risk of self-reported functional limitations (OR 2.41; 95% CI 1.71 to 3.41). Subjects with COPD with anxiety had a higher longitudinal risk of COPD exacerbation in Cox proportional hazards analysis after controlling for covariates (HR 1.39; 95% CI 1.007 to 1.90).

CONCLUSION

COPD is associated with a higher risk of anxiety. Once anxiety develops among patients with COPD, it is related to poorer health outcomes. Further research is needed to determine whether systematic screening and treatment of anxiety in COPD will improve health outcomes and prevent functional decline and disability.