Evaluating Chronic Disease

An important part of the Department of Health and Mental Hygiene’s function is to decide how best to allocate health care resources.  When the DOHMJH decides where to allocate resources to screen and treat for a disorder based on historical data, it must consider two scenarios in which it can inform the most people about a condition that needs treatment-

1)     The data could show that a region has lower than normal rates of a particular disease- in which case it is possible that there is a high rate of undiagnosed cases.

2)      The data could show that a particular region has a higher than normal rate of a particular disease- in which case there is a common factor (whether a result of the environment or the culture) that leads to high rates.

High Blood Pressure is a prime example of this situation, as it is a treatable condition that can largely go undetected until too much damage has been done.  To decide where it would be best to allocate resources in the detection of High Blood Pressure or in the treatment of High Blood Pressure, the Health Department can use two different viewpoints to analyze two different types of information from the Community Health Surveys-  the percentage of people who are taking medication for High Blood Pressure, and the percentage of people who are taking high blood pressure medication.

To test the first hypothesis, the Health Department evaluates where there are low rates of screening for High Blood Pressure:

Figure 1.- Screening Rates for High Blood Pressure: This map shows that there are several areas with relatively reduced rates of screening, which may be considered for increased screening.

To test the second hypothesis, we should look to see if there are any regions with unusually high rates of High Blood Pressure:

Figure 2- Rates of High Blood Pressure- This map illustrates differences in the rate of High Blood Pressure across New York City

Based on a comparison of the two maps and a quick glance at the data, we see that while the DOHMH can make some improvements in screening, the health care delivery system has been extremely successful in screening a significant majority of New Yorkers.   In most cases, over 90% of the population has been screened in the last year.  This leads us to look into the data set to find what other variable could contribute to this rate of High Blood Pressure.

One possible hypothesis is that being overweight or obese is associated with High Blood Pressure, as a result of either a sedentary lifestyle or poor diet.  A geographical comparison of these variables leads us to a map that shows some correlation that being overweight/obese is highly associated with also having high bloodpressure, as shown in Figure 3.

Figure 3- High Blood Pressure and Overweight/Obese Populations- As we can see, 3 of the 4 Neighborhoods with extremely elevated rates of High Blood Pressure also have elevated rates of overweight/obesity in the sample.