Publications

BACKGROUND

Ambient air pollution and tuberculosis (TB) have an impact on public health worldwide, yet associations between the two remain uncertain.

OBJECTIVE

We determined the impact of residential traffic on mortality during treatment of active TB.

METHODS

From 2000-2012, we enrolled 32,875 patients in California with active TB and followed them throughout treatment. We obtained patient data from the California Tuberculosis Registry and calculated traffic volumes and traffic densities in 100- to 400-m radius buffers around residential addresses. We used Cox models to determine mortality hazard ratios, controlling for demographic, socioeconomic, and clinical potential confounders. We categorized traffic exposures as quintiles and determined trends using Wald tests.

RESULTS

Participants contributed 22,576 person-years at risk. There were 2,305 deaths during treatment for a crude mortality rate of 1,021 deaths per 10,000 person-years. Traffic volumes and traffic densities in all buffers around patient residences were associated with increased mortality during TB treatment, although the findings were not statistically significant in all buffers. As the buffer size decreased, fifth-quintile mortality hazards increased, and trends across quintiles of traffic exposure became more statistically significant. Increasing quintiles of nearest-road traffic volumes in the 100-m buffer were associated with 3%, 14%, 19%, and 28% increased risk of death during TB treatment [first quintile, referent; second quintile hazard ratio (HR)=1.03 [95% confidence interval (CI): 0.86, 1.25]; third quintile HR=1.14 (95% CI: 0.95, 1.37); fourth quintile HR=1.19 (95% CI: 0.99, 1.43); fifth quintile HR=1.28 (95% CI: 1.07, 1.53), respectively; p-trend=0.002].

CONCLUSIONS

Residential proximity to road traffic volumes and traffic density were associated with increased all-cause mortality in patients undergoing treatment for active tuberculosis even after adjusting for multiple demographic, socioeconomic, and clinical factors, suggesting that TB patients are susceptible to the adverse health effects of traffic-related air pollution. https://doi.org/10.1289/EHP1699.

Patient-centered medical home models are fundamental to the advanced alternative payment models defined in the Medicare Access and Children's Health Insurance Plan Reauthorization Act (MACRA). The patient-centered medical home is a model of healthcare delivery supported by alternative payment mechanisms and designed to promote coordinated medical care that is simultaneously patient-centric and population-oriented. This transformative care model requires shifting reimbursement to include a per-patient payment intended to cover services not previously reimbursed such as disease management over time. Payment is linked to quality measures, including proportion of care delivered according to predefined pathways and demonstrated impact on outcomes. Some medical homes also include opportunities for shared savings by reducing overall costs of care. Recent proposals have suggested expanding the medical home model to specialized populations with complex needs because primary care teams may not have the facilities or the requisite expertise for their unique needs. An example of a successful care model that may provide valuable lessons for those creating specialty medical home models already exists in many hematopoietic cell transplantation (HCT) centers that deliver multidisciplinary, coordinated, and highly specialized care. The integration of care delivery in HCT centers has been driven by the specialty care their patients require and by the payment methodology preferred by the commercial payers, which has included bundling of both inpatient and outpatient care in the peritransplant interval. Commercial payers identify qualified HCT centers based on accreditation status and comparative performance, enabled in part by center-level comparative performance data available within a national outcomes database mandated by the Stem Cell Therapeutic and Research Act of 2005. Standardization across centers has been facilitated via voluntary accreditation implemented by Foundation for the Accreditation of Cell Therapy. Payers have built on these community-established programs and use public outcomes and program accreditation as standards necessary for inclusion in specialty care networks and contracts. Although HCT centers have not been described as medical homes, most HCT providers have already developed the structures that address critical requirements of MACRA for medical homes.

BACKGROUND

The current interstitial lung disease (ILD) classification has overlapping clinical presentations and outcomes. Cluster analysis modeling is a valuable tool in identifying distinct clinical phenotypes in heterogeneous diseases. However, this approach has yet to be implemented in ILD.

METHODS

Using cluster analysis, novel ILD phenotypes were identified among subjects from a longitudinal ILD cohort, and outcomes were stratified according to phenotypic clusters compared with subgroups according to current American Thoracic Society/European Respiratory Society ILD classification criteria.

RESULTS

Among subjects with complete data for baseline variables (N = 770), four clusters were identified. Cluster 1 (ie, younger white obese female subjects) had the highest baseline FVC and diffusion capacity of the lung for carbon monoxide (Dlco). Cluster 2 (ie, younger African-American female subjects with elevated antinuclear antibody titers) had the lowest baseline FVC. Cluster 3 (ie, elderly white male smokers with coexistent emphysema) had intermediate FVC and Dlco. Cluster 4 (ie, elderly white male smokers with severe honeycombing) had the lowest baseline Dlco. Compared with classification according to ILD subgroup, stratification according to phenotypic clusters was associated with significant differences in monthly FVC decline (Cluster 4, -0.30% vs Cluster 2, 0.01%; P < .0001). Stratification by using clusters also independently predicted progression-free survival (P < .001) and transplant-free survival (P < .001).

CONCLUSIONS

Among adults with diverse chronic ILDs, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might better predict meaningful clinical outcomes than current ILD diagnostic criteria.

Gene flow between populations may either support local adaptation by supplying genetic variation on which selection may act, or counteract it if maladapted alleles arrive faster than can be purged by selection. Although both such effects have been documented within plant species' native ranges, how the balance of these forces influences local adaptation in invasive plant populations is less clear, in part because introduced species often have lower genetic variation initially but also tend to have good dispersal abilities. To evaluate the extent of gene flow and adaptation to local climate in invasive populations of Solidago canadensis, and the implications of this for range expansion, we compared population differentiation at microsatellite and chloroplast loci for populations across Switzerland and assessed the effect of environmental transfer distance using common gardens. We found that while patterns of differentiation at neutral genetic markers suggested that populations are connected through extensive pollen and seed movement, common-garden plants nonetheless exhibited modest adaptation to local climate conditions. Growth rate and flower production declined with climatic distance from a plant's home site, with clones from colder home sites performing better at or above the range limit. Such adaptation in invasive species is likely to promote further spread, particularly under climate change, as the genotypes positioned near the range edge may be best able to take advantage of lengthening growing seasons to expand the range.