Of the146 attendees, 25% were doctors of veterinary medicine, 12% medical doctors or doctors of osteopathy, 10% nurses, and 54% were other healthcare or public health professionals. Of those completing both the pre- and post-tests, 25% were doctors of veterinary medicine, 14.3% were medical doctors or doctors of osteopathy, 8.9% were nurses, and the remaining 51.8% were other healthcare or public health professionals. Table 1 provides the means and standard deviations for each of the questions (truncated item) on the knowledge assessment. The table provides 1) the results for the pre- and post-tests, 2) the difference between the two tests, and 3) a 95% confidence interval for the difference.
Starting at item 3 in Table 1 (“Present in Texas?”), the values are associated with correct or incorrect answers and may be interpreted as percentages. Prior to the training, 96% were correct in understanding that the disease was present in Texas, and 84% knew that the disease was caused by a parasite rather than a virus, bacterium, or other. Only 30% knew that T. cruzi, the parasite that causes Chagas disease was not transmitted by the saliva of an infected triatome (but rather the feces). While 73% knew that Chagas disease was prevalent in the Southern United States, only 39% could identify that 21-40% of those infected develop clinical disease. Eighty percent knew the symptoms prior to training, and 73% identified the clinical manifestations with only 41% correctly identifying the laboratory methods used to diagnose Chagas disease. Fifty-two percent knew the treatment recommendations, and only 38% understood EKG findings associated with Chagas disease.
Table 1. Chagas disease (CD) knowledge pretest, posttest with difference means / standard deviations by survey question
|
Pre
|
Post
|
Post-Pre
|
Pre
|
Post
|
Post-Pre
|
Lower 95%
|
Upper 95%
|
Item (n=56)
|
Mean
|
Mean
|
Mean
|
SD
|
SD
|
SD
|
Post-Pre
|
Post-Pre
|
Describe your level of CD Knowledge
1 (I don't know anything); 2 (Very limited); 3 (Limited); 4 (Good); 5 (Excellent)
|
3.13
|
3.95
|
0.82
|
0.95
|
0.82
|
0.79
|
0.61
|
1.03
|
How confident are you with your CD Knowledge is current?
1 (Don't know); 2 (Not at all confident); 3 (Somewhat confident); 4 (Confident); 5 (Very confident)
|
2.84
|
3.96
|
1.13
|
1.01
|
0.93
|
1.08
|
0.84
|
1.41
|
CD is present in Texas? (True or False)
|
0.96
|
0.96
|
0.00
|
0.19
|
0.19
|
0.30
|
-0.08
|
0.08
|
Cause of CD
|
0.84
|
0.91
|
0.07
|
0.37
|
0.29
|
0.26
|
0.00
|
0.14
|
Transmission of CD
|
0.30
|
0.59
|
0.29
|
0.46
|
0.50
|
0.49
|
0.16
|
0.42
|
What part of the world is CD transmitted?
|
0.73
|
0.91
|
0.18
|
0.45
|
0.29
|
0.39
|
0.08
|
0.28
|
What % of patients develop clinical disease?
|
0.39
|
0.70
|
0.30
|
0.49
|
0.46
|
0.54
|
0.16
|
0.44
|
CD Symptoms
|
0.80
|
0.88
|
0.07
|
0.40
|
0.33
|
0.37
|
-0.03
|
0.17
|
CD Clinical Manifestations
|
0.73
|
0.89
|
0.16
|
0.45
|
0.31
|
0.42
|
0.05
|
0.27
|
Methods to diagnose CD
|
0.41
|
0.86
|
0.45
|
0.50
|
0.35
|
0.54
|
0.31
|
0.59
|
CD Treatment
|
0.52
|
0.77
|
0.25
|
0.50
|
0.43
|
0.44
|
0.14
|
0.36
|
EKG Typical of CD
|
0.38
|
0.48
|
0.11
|
0.49
|
0.50
|
0.56
|
-0.04
|
0.25
|
Figure 1 graphs the post-test less the pre-test mean scores. From this figure, it is clear that there were knowledge improvements for all questions except for one: True or False: Chagas disease is present in Texas.
A Wilcoxon rank sum test of self-assessed Chagas disease knowledge (“How would you describe your level of knowledge about Chagas disease?”) indicated a significant difference in pre-test versus post-test (V=35, p<.001). Self-assessed Chagas disease knowledge improved from a median of 3 to a median of 4. Another Wilcoxon rank sum test evaluated “How confident are you that your knowledge on Chagas disease is up to date?” Again, the results were statistically significant (V=39, p<.001).
McNemar Chi-Square tests were run for each of the knowledge questions in the survey. Table 2 provides the results. Pre-post statistically significant differences were found in 6 of the 10 questions including questions about how Chagas disease is transmitted (p<.001), where it is transmitted via vectors (p<.005) what percentage of infected individuals develop clinical disease (p<.001), what clinical manifestations occur (p=.016), laboratory methods of how Chagas disease is diagnosed (p<.001), and how Chagas disease is treated (p<.001). Of the 56 attendees, 96% knew in advance that Chagas disease was present in Texas, and that remained static after training. There were increases in knowledge for all other survey questions, even for those questions that were not statistically significant. Table 1 shows the post-pre-test mean differences.
Table 2. Chagas disease pre-post knowledge analysis of questions in survey
Question
|
McNemar c21
|
p-value
|
Present in Texas?
|
0.000
|
1.000
|
Cause of CD
|
2.250
|
0.134
|
Transmission of CD
|
12.500
|
<.001*
|
Where is CD transmitted?
|
8.100
|
<.005*
|
% Develop Clinical Disease
|
12.190
|
<.001*
|
Symptoms
|
1.125
|
0.289
|
Clinical Manifestations
|
5.818
|
0.016*
|
Methods to diagnose CD
|
21.333
|
<.001*
|
Treatment
|
12.071
|
<.001*
|
EKG Typical of CD
|
1.388
|
0.239
|
*Statistically significant at a value of <.05