Healthcare Disparities in Maine

Assessing Disparities in Access to Advanced Medical Device Therapy in Maine  

Abstract: This project aims to address accessibility disparities in rural and urban areas of Maine for medical assist devices like the Left Ventricle Assist Device (LVAD) by designing and distributing a non-invasive mock LVAD called XVAD. The study focuses on collecting user data to understand individual variations and improve training, ultimately addressing biases in access and use of advanced medical devices.  

Background: Heart disease is the primary cause of death in wealthy countries, with higher incidences in rural, lower-income areas. In Maine, heart disease cases are rising, particularly in rural regions, which may affect the demand for medical resources like LVADs. The full extent of these impacts is not yet fully understood.  Research Questions: The study investigates the efficacy of XVAD systems as a training device, addressing two questions:  1) Do XVADs provide necessary response training for better adaptation to LVAD implants? 2) Do XVADs simulate LVADs in terms of usage and quality of life effects? Data will be collected through diary-based journaling and measuring demographic covariates.  

Methods: The study uses data from the XVAD device to map learning curves associated with LVAD utilization. The response variables measured include accuracy of response to alarms and responsiveness to alarms. Participants are introduced to the device, respond to programmed alarms, and record their experiences in a diary. Data is analyzed using multilevel regression and cluster analysis.  

Preliminary Results: Preliminary results show participants' learning curves and sentiment analysis from focus groups. More data is needed to compare urban and rural learning curve behaviors. The final study aims to include 60 participants for more robust analysis.

Quantitative Analysis 

Participants wore an XVAD device for a week. The devices recored various metrics.

Response To Alarm Codes 

Our initial exploration of this data shows some interesting trends based on the frequency of the different alarms. Alarms for respective codes make different noises. We can see that some smoothed trend lines are monotonic while others are very non-monotonic. Codes which appear quite non-monotonic had a much lower frequency than other codes. There also appear to be some plateaus and regressions in the learning curves as time progress. It appears there might be a relationship between the total number of a certain codes played and a slower response time showing that participants are becoming conditioned to certain tones played by the XVAD device.  

Response Time Trend 

Negative Relationship between Alarm Response Time and Frequency. As the number of alarms responded to increases, there is a corresponding increase in response time, indicating a negative correlation. The intercept is estimated to be 5471.51 milliseconds and the slope coefficient for the predictor variable (response) is estimated to be -93.67 milliseconds. Both the intercept and the slope coefficient have p-values less than 0.05, indicating that they are statistically significant. The R-squared value is 0.1302, indicating that about 13% of the variability in the response variable can be explained by the predictor variable. The F-statistic is 15.26 with a p-value of 0.0001683, indicating that the model is statistically significant and that it provides a good fit to the data. Based on these results, we can conclude that there is a statistically significant negative linear relationship between the predictor variable x and the response variable y. For every one unit increase in an alarm, we expect to see a decrease of approximately 93.67 milliseconds. 

Logistic Regression

This is a logistic regression model with the response variable Pass and fail and predictor variable Time, using a binomial family. The model shows that the predictor variable Timelog has a positive coefficient of 3.7973, which means that for each one-unit increase in Timelog, the log-odds of a failing response increase by 3.7973. Both coefficients are statistically significant (p < 0.05), indicating that the relationship between the predictor variable and response variable is unlikely due to chance. Based on the findings from this logistic regression model, we can conclude that the log of the Time variable is a significant predictor of whether a participant will pass or fail to respond to an alarm. Additionally, the intercept of -33.7316 suggests that the log-odds of failing is very low when Timelog is zero, which may indicate a baseline level behavior before any intervention or treatment.

Bootstrapped Model

Bootstrapping is a powerful resampling technique that has gained popularity due to its ability to provide reliable estimates of standard errors and confidence intervals for various statistics, particularly in situations where direct standard error formulas are complex or unavailable. The fundamental concept of bootstrapping revolves around the notion that drawing conclusions about a population using sample data can be achieved by resampling the sample data and conducting inferences about a sample derived from the resampled data (resampled → sample → population).  We see the data starts form into a 'normal distribution' shape as we add more data points.

The results show an almost normal distrubiton. The black line is the boot strapped data and the red line is a normal distribution. It's clear they are very similar. Normal distributions are commonly observed in many natural and social phenomena, such as heights and weights of people, exam scores, and many physical and biological measurements. They are important because they have several properties that make them easy to work with mathematically and statistically. For example, the mean, median, and mode of a normal distribution are all equal, and the proportion of the data within a certain number of standard deviations of the mean can be easily calculated using the empirical rule or z-scores. 

When a dataset takes a normal distribution shape, it is often possible to use statistical tests and models that assume a normal distribution, such as the t-test, ANOVA, and linear regression. However, it is important to note that not all datasets follow a normal distribution, and it is important to check for normality and explore other distributional assumptions before applying these methods.

Confidence Interval results:

   5%        50%        95%

4676.242 5116.081   5525.220 

So, we can be 95% confident that, on average, XVAD users will respond to the XVAD alarms between 4676 and 5525 milliseconds. This is great as it means most users will respond at a passing rate. 

Focus Group Machine Learning Analysis

An interview or feedback session was conducted with the participant. Transcripts were made from consented recordings.

Focus Group Insight

Following phase 1, some participants engaged in focus groups. Sessions were recorded with consent and sentiment analysis of the transcribed discussions was performed. The sentiment analysis was performed on the transcribed discussions of focus groups to gain deeper insights into the participants' experience. Overall, the sentiment scores were positive across all groups. Sentiment analysis is a process of extracting subjective information from text data. It is a computational approach used to determine the attitude or opinion expressed in a piece of text, whether it is positive, negative, or neutral. Because the sentiment scores were heavier on the positive scale across all groups, we can infer that the participants had a positive attitude towards the topic of discussion. This is a good indication that the processes implemented has worked well. 

High Sentiment Tokens

The sentiment analysis process involves several steps. First, the text data is preprocessed, which involves removing stop words, punctuation, and other irrelevant information. Next, the text is tokenized, which involves splitting the text into individual words or phrases. Then, the sentiment of each token is determined based on the context in which it appears, using methods such as rule-based systems, machine learning models, or lexicon-based approaches.  Once the sentiment of each token has been determined, an overall sentiment score can be calculated for the entire text. This can be done by summing the sentiment scores of all tokens. 

High Contribution Words

For sentiment analysis to work well, stop words such as; like, the, and, of, etc. should be removed. Additionally, domain specific words like; 'alarm' should be removed as it likely refers to the task reminder, not causing the sensation of being alarmed or something being alarming. Removing domain-specific and stop words is beneficial for it improves the accuracy of models that process text data by removing irrelevant terms that may be specific to a particular field or industry and it can make the text more easily understandable to people who are not familiar with the specific field or industry being analyzed.   

Discussion / Next Steps:  The secondary phase of the study includes the recruitment of older adults in rural areas in Maine. These adults will be recruited through the Center on Aging, where flyers of information will be provided. The flyers will be distributed to research registry members via the Maine Older Adult Research Registry and the University of New England Legacy Scholars Program via e-mail and mail directly from registry administrators. Additional recruitment will include the Center on Aging newsletter and newsletters of Maine area agencies on aging. The recruitment process will follow the same steps as outlined for Phase I and will rely heavily on e-mail distribution of the recruitment flyer. Recruitment via the registries and Area Agencies on Aging has been a successful recruitment strategy for prior research projects carried out at the UMaine Center on Aging. We will also look further into how rural and urban healthcare access differs in that rural communities tend to seek hospital care less frequently. This is important as the prevalence of heart disease increases, and there is a greater need for external heart devices. Clear user understanding and ability to use these devices are critical. Identifying issues with user-device interface during training can increase chances of success and survival, especially if training is completed before device use.  

Insight From Focus Groups

Following phase 1, some participants engaged in focus groups. Sessions were recorded with consent and sentiment analysis of the transcribed discussions was performed. The sentiment analysis was performed on the transcribed discussions of focus groups to gain deeper insights into the participants' experience. Overall, the sentiment scores were positive across all groups. Sentiment analysis is a process of extracting subjective information from text data. It is a computational approach used to determine the attitude or opinion expressed in a piece of text, whether it is positive, negative, or neutral. Because the sentiment scores were heavier on the positive scale across all groups, we can infer that the participants had a positive attitude towards the topic of discussion. This is a good indication that the processes implemented has worked well.