Hits and misses: screening commercial drivers for obstructive sleep apnea using guidelines recommended by a joint task force.

OBJECTIVE: To evaluate joint task force criteria-based screening for severe obstructive sleep apnea (s-OSA) in commercial drivers. METHODS: Among a community-based cohort of licensed commercial vehicle drivers, we assessed utility of the joint task force criteria. We conducted full, 14-channel overnight polysomnography in all drivers, defining s-OSA as an apnea-hypopnea index of 30 or more per hour. RESULTS: One hundred of 104 drivers with successful polysomnography studies were predominantly obese (median body mass index = 32.8 kg/m; interquartile range = 26.8 to 37.4) and had a median apnea-hypopnea index of 20.6 per hour (interquartile range = 10.0 to 34.2). Examination-based criteria were more effective (sensitivity = 80%; negative posttest probability [nPTP] = 17%) than symptom-based criteria (sensitivity = 63%; nPTP = 23%). Examination and symptom-based criteria combined had high sensitivity (97%) and low nPTP (7%), but poor specificity (19%). CONCLUSIONS: Examination-based criteria missed 20% of s-OSA cases. Combining examination with confidentially reported symptoms improved sensitivity but required confirmatory polysomnography in 86%, supporting universal screening of all drivers.

Can we predict daily adherence to warfarin?: Results from the International Normalized Ratio Adherence and Genetics (IN-RANGE) Study.

BACKGROUND: Warfarin is the primary therapy to prevent stroke and venous thromboembolism. Significant periods of nonadherence frequently go unreported by patients and undetected by providers. Currently, no comprehensive screening tool exists to help providers assess the risk of nonadherence at the time of initiation of warfarin therapy. METHODS: This article reports on a prospective cohort study of adults initiating warfarin therapy at two anticoagulation clinics (university- and Veterans Affairs-affiliated). Nonadherence, defined by failure to record a correct daily pill bottle opening, was measured daily by electronic pill cap monitoring. A multivariable logistic regression model was used to develop a point system to predict daily nonadherence to warfarin. RESULTS: We followed 114 subjects for a median of 141 days. Median nonadherence of the participants was 14.4% (interquartile range [IQR], 5.8-33.8). A point system, based on nine demographic, clinical, and psychosocial factors, distinguished those demonstrating low vs high levels of nonadherence: four points or fewer, median nonadherence 5.8% (IQR, 2.3-14.1); five points, 9.1% (IQR, 5.9-28.6); six points, 14.5% (IQR, 7.1-24.1); seven points, 14.7% (IQR, 7.0-34.7); and eight points or more, 29.3% (IQR, 15.5-41.9). The model produces a c-statistic of 0.66 (95% CI, 0.61-0.71), suggesting modest discriminating ability to predict day-level warfarin nonadherence. CONCLUSIONS: Poor adherence to warfarin is common. A screening tool based on nine demographic, clinical, and psychosocial factors, if further validated in other patient populations, may help to identify groups of patients at lower risk for nonadherence so that intensified efforts at increased monitoring and intervention can be focused on higher-risk patients.

Adherence to sleep apnea therapy and use of lipid-lowering drugs: a study of the healthy-user effect.

BACKGROUND: Evidence that continuous positive airway pressure (CPAP) reduces cardiovascular morbidity comes largely from observational studies. This association may be confounded if CPAP adherents are healthier in ways not measured by investigators. We assessed whether patients adhering to lipid-lowering medications were more adherent to CPAP. METHODS: This was a retrospective cohort study undertaken at the Philadelphia Veterans Affairs (VA) Medical Center (2005-2006) of consecutive patients on lipid-lowering therapy newly initiating CPAP for obstructive sleep apnea. Adherence to medications dispensed via the VA closed-pharmacy system was measured as the proportion of days covered (>/=80% vs < 80%) in the year prior to CPAP initiation. CPAP adherence was defined as >/= 4 h/d of "mask-on" time, measured electronically daily during the first week of CPAP. We examined the association between medication adherence and CPAP adherence using multivariable logistic regression. RESULTS: Complete data were available for 117 of 142 (81.5%) subjects. After adjustment for age, race, medical comorbidity, and sleep apnea-related clinical factors, subjects with low medication adherence demonstrated a 40.1% (95% CI, 30.0-51.0) probability of using CPAP >/= 4 h/d compared with 55.2% (95% CI, 46.9-63.1) for subjects with adequate (>/=80%) medication adherence (adjusted for comparison, odds ratio (OR) = 1.8 [95% CI, 1.0-3.3], P = .04). Married patients were more adherent to medications and CPAP; inclusion of this factor reduced to nonsignificance the association of medication and CPAP adherence (OR = 1.6 [95% CI, 0.9-2.8], P = .12). CONCLUSION: Patients consistently refilling lipid-lowering medications were more adherent to CPAP, suggesting that differences in medication adherence or other health-promoting behaviors should be investigated in future nonrandomized, observational studies linking CPAP adherence and cardiovascular outcomes.

Patient attitudinal and behavioral factors associated with warfarin non-adherence at outpatient anticoagulation clinics.

BACKGROUND: Warfarin is an anticoagulant effective in preventing stroke, but it has a narrow therapeutic range requiring optimal adherence to achieve the most favorable effects. PURPOSE: The goal of this study was to examine specific patient factors that might help explain warfarin non-adherence at outpatient anticoagulation clinics. METHOD: In a prospective cohort study of 156 adults, we utilized logistic regression analyses to examine the relationship between the five Treatment Prognostics scales from the Millon Behavioral Medicine Diagnostic (MBMD), as well as three additional MBMD scales (Depression, Future Pessimism, and Social Isolation), and daily warfarin non-adherence assessed using electronic medication event monitoring systems caps over a median of 139 days. RESULTS: Four of the five Treatment Prognostic scales and greater social isolation were associated with warfarin non-adherence. When controlling for pertinent demographic and medical variables, the Information Discomfort scale remained significantly associated with warfarin non-adherence over time. CONCLUSION: Although several factors were related to warfarin non-adherence, patients reporting a lack of receptivity to details regarding their medical illness seemed most at risk for warfarin non-adherence. This information might aid in the development of interventions to enhance warfarin adherence and perhaps reduce adverse medical events.

Neighborhood of residence is associated with daily adherence to CPAP therapy.

STUDY OBJECTIVES: Adherence to continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea is poor. Risk factors for nonadherence are not well understood but may reflect individual or neighborhood socioeconomic factors. We sought to determine the association of socioeconomic status and initial CPAP adherence. DESIGN: Retrospective cohort study, 2005 to 2006. SETTING: Philadelphia VA Medical Center. PARTICIPANTS: Of 330 consecutive veterans who met study criteria for initiation of CPAP therapy for newly diagnosed sleep apnea, 266 had complete data for study inclusion. INTERVENTIONS: N/A. MEASUREMENTS: Through a multivariable logistic regression model, using an outcome of objectively measured CPAP use - 4 h daily during the first week of treatment, we tested whether patients from higher socioeconomic neighborhoods had higher CPAP adherence. We measured neighborhood socioeconomic status with an index derived from the 2000 U.S. Census at the block group-level composed of median household income, male and female employment, adult high school completion, married households, and minority composition. RESULTS: CPAP adherence > 4 h occurred on 48.9% of 1,805 patient-days observed for the 266 subjects. After adjustment for individual sociodemographic characteristics and medical comorbidity, the probability of daily CPAP use 4 h ranged from 34.1% (95% CI, 26.4-42.7) for subjects from a low socioeconomic neighborhood (5th percentile) to 62.3% (95% CI, 53.8-70.1) for subjects from a high (95th percentile) neighborhood. CONCLUSIONS: In a retrospective cohort of veterans, initial CPAP adherence was closely associated with higher neighborhood socioeconomic factors. Future investigation should target specific impediments to adherence in the home and neighborhood environment.

Risk factors for nonadherence to warfarin: results from the IN-RANGE study.

BACKGROUND: Warfarin is widely used to prevent stroke and venous thromboembolism despite its narrow therapeutic window. Warfarin nonadherence is a substantial problem, but risk factors have not been well elucidated. METHODS: A prospective cohort study of adults initiating warfarin at two anticoagulation clinics (University and VA-affiliated) was performed to determine factors affecting nonadherence to warfarin. Nonadherence, defined by failure to record a correct pill bottle opening each day, was measured daily via electronic medication event monitoring systems (MEMS) caps. A multivariable explanatory model using logistic regression for longitudinal data was used to identify risk factors for nonadherence. RESULTS: One hundred eleven subjects were followed for a median of 137 days. Warfarin nonadherence was common (4787 of 22,425 or 21% of patient-days observed). Factors independently associated with higher odds of nonadherence included education beyond high school (odds ratio (OR) 1.8 (95%CI 1.2-2.7)), lower Short Form (SF)-36 mental component score (OR 1.4 (1.1-1.6) for each 10 point decrease); and impaired cognition (< or =19 points) on the Cognitive Capacity Screening Examination (CCSE) (OR 2.9 (1.7-4.8)). Compared to currently employed subjects, unemployed (OR 0.6 (0.3-1.2)) and retired (OR 0.5 (0.3-0.8)) subjects had somewhat improved adherence; disabled subjects over age 55 had worse adherence (OR 1.8 (1.1-3.1)) than younger disabled subjects (OR 0.8 (0.4-1.5)). CONCLUSIONS: Poor adherence to warfarin is common and risk factors are related to education level, employment status, mental health functioning, and cognitive impairment. Within the carefully controlled anticoagulation clinic setting, such patient-specific factors may be the basis of future interventions to improve nonadherence.