Socioeconomic Burden of Rising Methamphetamine-Associated Heart Failure Hospitalizations in California From 2008 to 2018.

BACKGROUND: Methamphetamine-associated cardiomyopathy/heart failure (MethHF) is an increasingly recognized disease entity in the context of a rising methamphetamine (meth) epidemic that most severely impacts the western United States. Using heart failure (HF) hospitalization data from the Office of Statewide Health Planning and Development, this study aimed to assess trend and disease burden of MethHF in California. METHODS: Adult patients (≥18 years old) with HF as primary hospitalization diagnosis between 2008 and 2018 were included in this study. The association with Meth (MethHF) and those without (non-MethHF) were determined by meth-related International Classification of Diseases-based secondary diagnoses. Statistical significance of trends in age-adjusted rates of hospitalization per 100 000 adults were evaluated using nonparametric analysis. RESULTS: Between 2008 and 2018, 1 033 076 HF hospitalizations were identified: 42 565 were MethHF (4.12%) and 990 511 (95.88%) were non-MethHF. Age-adjusted MethHF hospitalizations per 100 000 increased by 585% from 4.1 in 2008 to 28.1 in 2018, while non-MethHF hospitalizations decreased by 6.0% from 342.3 in 2008 to 321.6 in 2018. The rate of MethHF hospitalization increase more than doubled that of a negative control group with urinary tract infection and meth-related secondary diagnoses (7.82-fold versus 3.48-fold, P<0.001). Annual inflation-adjusted hospitalization charges because of MethHF increased by 840% from $41.5 million in 2008 to $390.2 million in 2018, as compared with an 82% increase for all HF hospitalization from $3.503 billion to $6.376 billion. Patients with MethHF were significantly younger (49.64±10.06 versus 72.20±14.97 years old, P<0.001), predominantly male (79.1% versus 52.4%, P<0.001), with lower Charlson Comorbidity Index, yet they had longer length of stay, more hospitalizations per patient, and more procedures performed during their stays. CONCLUSIONS: MethHF hospitalizations increased sharply during the study period and contributed significantly to the HF hospitalization burden in California. This emerging HF phenotype, which engenders considerable financial and societal costs, calls for an urgent and concerted public health response to contain its spread.

Heterogeneous Reactions of Limonene on Mineral Dust: Impacts of Adsorbed Water and Nitric Acid.

Biogenic volatile organic compounds (BVOCs), including the monoterpene limonene, are a major source of secondary organic aerosol (SOA). While gas-phase oxidation initiates the dominant pathway for BVOC conversion to SOA, recent studies have demonstrated that biogenic hydrocarbons can also directly react with acidic droplets. To investigate whether mineral dust may facilitate similar reactive uptake of biogenic hydrocarbons, we studied the heterogeneous reaction of limonene with mineral substrates using condensed-phase infrared spectroscopy and identified the formation of irreversibly adsorbed organic products. For kaolinite, Arizona Test Dust, and silica at 30% relative humidity, GC-MS identified limonene-1,2-diol as the dominant product with total organic surface concentrations on the order of (3-5) × 1018 molecules m-2. Experiments with 18O-labeled water support a mechanism initiated by oxidation of limonene by surface redox sites forming limonene oxide followed by water addition to the epoxide to form limonenediol. Limonene uptake on α-alumina, γ-alumina, and montmorillonite formed additional products in high yield, including carveol, carvone, limonene oxide, and α-terpineol. To model tropospheric processing of mineral aerosol, we also exposed each mineral substrate to gaseous nitric acid prior to limonene uptake and identified similar surface adsorbed products that were formed at rates 2 to 5 times faster than without nitrate coatings. The initial rate of reaction was linearly dependent on gaseous limonene concentration between 5 × 1012 and 5 × 1014 molecules cm-3 (0.22-20.5 ppm) consistent with an Eley-Rideal-type mechanism in which gaseous limonene reacts directly with reactive surface sites. Increasing relative humidity decreased the amount of surface adsorbed products indicating competitive adsorption of surface adsorbed water. Using a laminar flow tube reactor we measured the uptake coefficient for limonene on kaolinite at 25% RH to range from γ = 5.1 × 10-6 to 9.7 × 10-7. After adjusting for reactive surface areas, we estimate uptake coefficients for limonene on HNO3-processed mineral aerosol on the order of (1-6) × 10-6. Although this heterogeneous reaction will not impact the atmospheric lifetime of gaseous limonene, it does provide a new pathway for mineral aerosol to acquire secondary organic matter from biogenic hydrocarbons, which in turn will alter the physical properties of mineral dust.