Characteristics of pulse oximetry and arterial blood gas in patients with fibrotic interstitial lung disease.

BACKGROUND: Fibrotic interstitial lung disease (ILD) is frequently associated with abnormal oxygenation; however, little is known about the accuracy of oxygen saturation by pulse oximetry (SpO2) compared with arterial blood gas (ABG) saturation (SaO2), the factors that influence the partial pressure of carbon dioxide (PaCO2) and the impact of PaCO2 on outcomes in patients with fibrotic ILD. STUDY DESIGN AND METHODS: Patients with fibrotic ILD enrolled in a large prospective registry with a room air ABG were included. Prespecified analyses included testing the correlation between SaO2 and SpO2, the difference between SaO2 and SpO2, the association of baseline characteristics with both the difference between SaO2 and SpO2 and the PaCO2, the association of baseline characteristics with acid-base category, and the association of PaCO2 and acid-base category with time to death or transplant. RESULTS: A total of 532 patients with fibrotic ILD were included. Mean resting SaO2 was 92±4% and SpO2 was 95±3%. Mean PaCO2 was 38±6 mmHg, with 135 patients having PaCO2 <35 mmHg and 62 having PaCO2 >45 mmHg. Correlation between SaO2 and SpO2 was mild to moderate (r=0.39), with SpO2 on average 3.0% higher than SaO2. No baseline characteristics were associated with the difference in SaO2 and SpO2. Variables associated with either elevated or abnormal (elevated or low) PaCO2 included higher smoking pack-years and lower baseline forced vital capacity (FVC). Lower baseline lung function was associated with an increased risk of chronic respiratory acidosis. PaCO2 and acid-base status were not associated with time to death or transplant. INTERPRETATION: SaO2 and SpO2 are weakly-to-moderately correlated in fibrotic ILD, with limited ability to accurately predict this difference. Abnormal PaCO2 was associated with baseline FVC but was not associated with outcomes.

Comorbidity and polypharmacy among women living with HIV in British Columbia.

OBJECTIVE: To characterize comorbid disease and medication burden among women living with HIV (WLWH) in British Columbia (BC), Canada. DESIGN: We examined baseline data from 267 WLWH and 276 HIV-negative women, aged at least 19 years, enrolled in the Children and Women: Antiretrovirals and Markers of Aging (CARMA) cohort. METHODS: Self-reported demographic, medical condition, medication, vitamin, and substance exposure data were collected at baseline CARMA study visits. We considered conditions with appropriate concomitant medications to be 'treated'. Wilcoxon rank-sum and Fisher's exact tests compared continuous and categorical variables between WLWH and HIV-negative women. Number of diagnoses, prescribed medications (excluding HIV/antiretrovirals), vitamins, and prevalence of depression/anxiety/panic disorder were compared using negative binomial and logistic regressions for continuous and binary variables, respectively. RESULTS: WLWH were younger [median, interquartile range (IQR) 39.9, 33.6-46.9 vs. 43.6, 31.8-54.6 years; P = 0.01], attained lower education (40.5 vs. 69.6% college/university; P < 0.001), and more often currently smoked tobacco (47.9 vs. 31.9%; P < 0.001) or had income less than $15 000/year (49.0 vs. 43.1%; P < 0.001). Although younger, and despite omitting HIV infection, WLWH had a greater number of diagnoses (incidence rate ratio, 95% confidence interval 1.58, 1.38-1.81; P < 0.001), and more depression/anxiety/panic disorder vs. controls (odds ratio, 95% CI 1.86, 1.22-2.83; P = 0.004). Our model predicts that with mean BMI (26.3), WLWH and HIV-negative peers would have two comorbid diagnoses by age 30 and 60, respectively. CONCLUSIONS: WLWH living in BC have more comorbid illness earlier in life than their HIV-negative peers, and have very high rates of depression/anxiety/panic disorder. Addressing mental health and comorbid conditions is essential to improving health outcomes among WLWH.