Altogether, 1175 patients with COVID-19 were admitted between 1st April and 15th May 2021. However, 210 of these patients were excluded from the study as they were allowed to go on home leave and hence did not have adequate inpatient documentation. Of the remaining 965 patients, 307 died during their hospital stay while 658 were successfully discharged (Figure 1). Table-1 presents the comparison of demographic and clinical factors such as signs and symptoms at the time of admission, the presence of comorbidities like hypertension, diabetes, cardio-vascular diseases, asthma, chronic kidney disease etc. and disease severity on admission between those who received ivermectin and those who did not. Except cough and weakness, all factors were similarly distributed between the two groups (Chi-square test p-value > 0.05).
Table-1: Comparison of demographic and clinical factors between patients receiving and not receiving ivermectin
Variables
|
Ivermectin
(n=171)
|
No ivermectin
(n=794)
|
Total
(n=965)
|
Chi-square value
|
p-value
|
Gender
Male
Female
|
128 (75%)
43 (25%)
|
549 (69%)
245 (31%)
|
677
288
|
2.19
|
0.139
|
Age Group
<25 years
25 – 44
45 above
|
8 (4.7%)
42 (24.6%)
121 (70.7%)
|
18 (2.3%)
207 (26.1%)
569 (71.6%)
|
26
249
690
|
3.17
|
0.204
|
Fever
Yes
No
|
115 (67.3%)
56 (32.7%)
|
475 (59.8%)
319 (40.2%)
|
590
375
|
3.267
|
0.071
|
Shortness of Breath
Yes
No
|
98 (57.3%)
73 (42.7%)
|
460 (57.9%)
334 (42.1%)
|
558
407
|
0.0255
|
0.881
|
Cough
Yes
No
|
92 (53.8%)
79 (48.2%)
|
357 (45%)
437 (55%)
|
449
516
|
4.418
|
0.036
|
Weakness
Yes
No
|
8 (4.7%)
163 (95.3%)
|
50 (6.3%)
744 (93.7%)
|
58
907
|
0.6527
|
0.0419
|
Headache
Yes
No
|
11 (6.4%)
160 (93.6%)
|
35 (4.4%)
759 (95.6%)
|
46
919
|
1.27
|
0.26
|
Hypertension
Yes
No
|
70 (40.9%)
101(59.1%)
|
334 (42.1%)
460 (57.9%)
|
404
561
|
0.0738
|
0.786
|
Diabetes
Yes
No
|
63 (36.8%)
108 (63.2%)
|
291 (36.6%)
503 (63.4%)
|
354
611
|
0.0022
|
0.960
|
Cardiovascular disease
Yes
No
|
51 (71.8%)
120 (28.2)
|
254 (32%)
540 (68%)
|
305
660
|
0.305
|
0.581
|
Asthma
Yes
No
|
6 (3.5%)
165 (96.5%)
|
25 (3.1%)
769 (96.9%)
|
31
934
|
0.0587
|
0.809
|
CKD
Yes
No
|
2 (1.2%)
169 (98.8%)
|
23 (2.9%)
771 (97.1%)
|
25
940
|
1.66
|
0.197
|
Disease Severity
Mild
Moderate
Severe
|
48 (28.1%)
49 (28.6%)
74 (43.3%)
|
239 (30.1%)
203 (25.6%)
352 (44.3%)
|
287
252
426
|
0.74
|
0.689
|
ICU Admission
Yes
No
|
46 (26.9%)
125 (73.1%)
|
221 (27.8%)
573 (72.2%)
|
267
698
|
0.0612
|
0.0643
|
Table-2 presents the comparison of various drugs administered between patients who were treated with ivermectin and those who were not. Altogether 171 (17.7%) received ivermectin in addition to other medicines such as antibiotics (168), steroids (161), remdesvir (83), toclizumab (4) and itolizumab (1). The remaining 794 who did not receive ivermectin were also treated with the above medicines as per the institutional protocol and the clinical judgement of the treating team. Usage of all drugs between the two groups was comparable (Chi-square test p-value>0.05).
Table-2: Comparison of usage of various drugs between patients receiving and not receiving ivermectin
Variables
|
Ivermectin
(n=171)
|
No ivermectin
(n=794)
|
Total
(n=965)
|
Chi-square value
|
p-value
|
Antibiotic
Yes
No
|
168 (98.2)
3 (1.8)
|
778 (98%)
16 (2%)
|
946
19
|
0.0946
|
0.824
|
Steroid
Yes
No
|
161 (97.7%)
10 (2.3%)
|
731 (97.1)
63 (2.9%)
|
892
73
|
0.876
|
0.349
|
Remdesvir
Yes
No
|
83 (48.5)
88 (51.5)
|
352 (44.3%)
442 (55. 7%)
|
435
530
|
1.0051
|
0.316
|
Toclizumab
Yes
No
|
4 (2.3%)
167 (97.7%)
|
38 (4.8%)
756 (95.2%)
|
42
923
|
2.02
|
0.155
|
Itlizumab
Yes
No
|
1 (0.6%)
170 (99.4%)
|
11 (1.4%)
783 (98.6%)
|
12
953
|
0.7343
|
0.391
|
Table-3 presents the effect of ivermectin on survival. The proportion of cases treated with ivermectin was 17.26% among the non-survivors and 17.93% among the survivors. The effect was statistically insignificant (crude OR = 0.954 ;95% CI: 0.668 – 1.364, p=0.80).
A logistic regression analysis was performed with bootstrapping after 50 replications of the random data set to estimate the effect of ivermectin on the outcome i.e. survival status after controlling for each of the confounders. Even after adjusting for the confounders, the effect was statistically not significant (adjusted OR = 0.96; 95% CI: 0.66 – 1.39, p= 0.819). The logistic regression model was found to fit well (Wald chi-square with 5 d.f. = 41.52, P =0.00001). The AIC was 1155.44 and BIC was -29.33.
Table-3: Association of ivermectin with survival
Ivermectin
|
Case
(Non-survivors)
(n=307)
|
Control (Survivors)
(n=658)
|
Total
(n=965)
|
Odds Ratio (95% CI)
|
Chi-square value
|
p-value
|
Yes
No
|
53 (17.26%)
254
|
118 (17.93%)
540
|
171
794
|
0.95 (0.67 – 1.36)*
0.96 (0.66 – 1.39)**
|
0.0643
0.0529
|
0.800
0.819
|
*-Crude OR; **-Adjusted OR
Effect of ivermectin on duration of hospital stay among the survivors
Table-4 presents the duration of hospital stay in days. It was tested for normality using Shapiro-Wilk W test. It was found to be non-normally distributed (z-statistic = 10.261, p-value=0.0001). Hence Mann-Whitney Wilcoxon U-test was applied to compare the distribution of hospital stay between the survivors who received ivermectin and those who did not. There was no significant difference between the two group (p=0.8759).
Table-4: Comparison of duration of hospital stay (in days) among survived Covid-19 patients
Ivermectin
|
n
|
Hospital Stay (In days)
Median (IQR)
|
MW
U-test Statistics
|
P-value
|
Yes
No
|
118
540
|
11 (7 – 15)
11 (7 – 16)
|
0.152
|
0.8759
|