An evaluation of rural-urban disparities in treatment outcomes for obstructive sleep apnoea: study protocol for a prospective cohort study

Evaluating methods to define place of residence in Canadian administrative data and the impact on observed associations with all-cause mortality in type 2 diabetes

PURPOSE

An individual's location of residence may impact health, however, health services and outcomes research generally use a single point in time to define where an individual resides. While this estimate of residence becomes inaccurate when the study subject moves, the impact on observed associations is not known. This study quantifies the impact of different methods to define residence (rural, urban, metropolitan) on the association with all-cause mortality.

METHODS

A diabetes cohort of new metformin users was identified from administrative data in Alberta, Canada between 2008 and 2019. An individual's residence (rural/urban/metropolitan) was defined from postal codes using 4 different methods: residence defined at 1-year before first metformin (this served as the reference model), comparison 1- stable residence for 3 years before first metformin, comparison 2- residence as time-varying (during the outcome observation window), and comparison 3 - nested case control (residence closest to the index date after identifying cases and controls). Multivariable Cox proportional hazard and logistic regression models were constructed to examine the association between residence definitions and all-cause mortality.

RESULTS

We identified 157,146 new metformin users (mean age of 55 years and 57% male) and 8,444 (5%) deaths occurred during the mean follow up of 4.7 (SD 2.3) years. There were few instances of moving after first metformin; 2.6% of individuals moved to a smaller centre (metropolitan to urban or rural, or urban to rural) and 3.1% moved to a larger centre (rural to urban or metropolitan, or urban to metropolitan). The association between rural residence and all-cause mortality was consistent (aHR:1.18; 95%CI:1.12-1.24), regardless of the method used to define residence.

CONCLUSIONS

The method used to define residence in a population of adults newly treated with metformin for type 2 diabetes has minimal impact on measures of all-cause mortality, possibly due to infrequent migration. The observed association between residence and mortality is compelling but requires further investigation and more robust analysis.

Rural Residence Is Associated With a Delayed Trend Away From Sulfonylurea Use for Treatment Intensification of Type 2 Diabetes

OBJECTIVE

To examine the intersection between location of residence along the rural-urban continuum (metropolitan, urban, and rural) and sulfonylurea dispensation records for the management of type 2 diabetes.

RESEARCH DESIGN AND METHODS

This retrospective cohort study used administrative health records of adult new metformin users between April 2008 and March 2019 in Alberta, Canada. Multivariable logistic regression was performed to examine the association between sulfonylurea-based treatment intensification and location of residence.

RESULTS

Treatment was intensified in 66,084 (38%) of 171,759 new metformin users after a mean of 1.5 years. At treatment intensification, mean age was 55 years, 62% of users were male, and 27% were rural residents. The most common antihyperglycemic drug, given to 30,297 people (46%) for treatment intensification, was a sulfonylurea. At the beginning of our observation period, the proportion of people dispensed a sulfonylurea at first treatment intensification was highest in rural (57%), compared with urban (54%) and metropolitan (52%) areas (P = 0.009). Although proportions decreased over time across the province, rural residents continued to constitute the highest proportion of sulfonylurea users (45%), compared with urban (35%) and metropolitan (37%) residents (P < 0.001), and the trend away from sulfonylurea use was delayed by ∼4 years for rural residents. Adjusting for potential sources of confounding, rural residence was associated with a significantly higher likelihood of using a sulfonylurea compared with metropolitan residence (adjusted odds ratio 1.34; 95% CI 1.29-1.39).

CONCLUSIONS

Variation in sulfonylurea dispensation across the rural-urban continuum provides a basis for continued research in the differences in process of care by location.

Environmental Benefits of Sleep Apnoea Detection in the Home Environment

Sleep Apnoea (SA) is a common chronic illness that affects nearly 1 billion people around the world, and the number of patients is rising. SA causes a wide range of psychological and physiological ailments that have detrimental effects on a patient’s wellbeing. The high prevalence and negative health effects make SA a public health problem. Whilst the current gold standard diagnostic procedure, polysomnography (PSG), is reliable, it is resource-expensive and can have a negative impact on sleep quality, as well as the environment. With this study, we focus on the environmental impact that arises from resource utilisation during SA detection, and we propose remote monitoring (RM) as a potential solution that can improve the resource efficiency and reduce travel. By reusing infrastructure technology, such as mobile communication, cloud computing, and artificial intelligence (AI), RM establishes SA detection and diagnosis support services in the home environment. However, there are considerable barriers to a widespread adoption of this technology. To gain a better understanding of the available technology and its associated strength, as well as weaknesses, we reviewed scientific papers that used various strategies for RM-based SA detection. Our review focused on 113 studies that were conducted between 2018 and 2022 and that were listed in Google Scholar. We found that just over 50% of the proposed RM systems incorporated real time signal processing and around 20% of the studies did not report on this important aspect. From an environmental perspective, this is a significant shortcoming, because 30% of the studies were based on measurement devices that must travel whenever the internal buffer is full. The environmental impact of that travel might constitute an additional need for changing from offline to online SA detection in the home environment.

Impact of wait times for treatment on clinical outcomes in patients with obstructive sleep apnoea: protocol for a randomised controlled trial

Background

Obstructive sleep apnoea (OSA) is a common chronic condition that is associated with significant morbidity and economic cost. Prolonged wait times are increasingly being recognised as a barrier to diagnosis and treatment of many chronic diseases; however, no study to date has prospectively evaluated the impact of wait times on health outcomes in OSA.

Objective

The purpose of this study is to determine whether treatment outcomes for individuals with OSA differ between patients managed using an expedited versus standard pathway.

Methods

A pragmatic randomised controlled trial design will be used with a target sample size of 200 adults. Participants with clinically significant uncomplicated OSA will be recruited through referrals to a large tertiary care sleep centre (Calgary, AB, Canada) and randomised to either early management (within 1 month) or usual care (∼6 months) with a 1:1 allocation using a concealed computer-generated randomisation sequence. The primary outcome will be adherence to positive airway pressure (PAP) therapy at 3 months after treatment initiation. Secondary outcomes will include change in sleepiness, quality of life, patient satisfaction, and patient engagement with therapy from baseline to 3 months after PAP initiation, measured using validated questionnaires and qualitative methods.

Anticipated results

This study will determine whether expedited care for OSA leads to differences in PAP adherence and/or patient-reported outcomes. More broadly, the findings of this study may improve the understanding of how wait time reductions impact health outcomes for other chronic diseases.

This study will determine whether expedited care for OSA leads to differences in PAP adherence and/or patient-reported outcomeshttps://bit.ly/38TrkwS

Treatment outcomes among rural and urban patients with obstructive sleep apnea: a prospective cohort study

STUDY OBJECTIVES

To determine whether adherence to continuous positive airway pressure (CPAP) in adults with uncomplicated OSA differs by rural versus urban residential address.

METHODS

In this prospective cohort study, we recruited adults who initiated CPAP for uncomplicated OSA that was diagnosed by a physician using sleep specialist-interpreted diagnostic testing. Participants were classified as urban (community size > 100,000) or rural by translating residential postal code into geographic census area. The primary outcome was mean daily hours of CPAP use compared between rural and urban patients. Secondary outcomes included: the proportion of patients who were adherent to CPAP; change in Epworth Sleepiness Scale (ESS) score; change in EuroQOL-5D score; and Visit-Specific Satisfaction Instrument score. All outcomes were measured three months after CPAP initiation.

RESULTS

We enrolled 242 patients (100 rural) with mean (SD) age 51 (13) years and respiratory event index 24 (18) events/hour. Mean (95% CI) CPAP use was 3.19 (2.8,3.58) hours/night and 35% were CPAP-adherent, with no difference between urban and rural patients. Among the 65% of patients who were using CPAP at three months, mean CPAP use was 4.89 (4.51,5.28) hours/night and was not different between rural and urban patients. Improvement in ESS and patient satisfaction were similar between groups, but EuroQOL-5D score improved to a greater extent in rural patients. Urban or rural residence was not associated with CPAP adherence in multivariable regression analysis.

CONCLUSIONS

Rural versus urban residence was not associated with differences in CPAP adherence when guided by specialist-interpreted diagnostic sleep testing.