At baseline, the age of the women in control and intervention groups ranged between 18 to 45 years with a mean age of 27. Very few women in control and intervention group (16&13%) had completed primary school education and most were uneducated. More than 60% of the women were married off at or earlier than 18 years of age. More than half of the women in both groups had three to four children. Most women lived in mud houses consisting of three to four rooms (>0.05), did not own a mobile phone, and they did not have an improved source of drinking water, latrine and sewage drainage system in their households. Approximately 35% and 20% women in control and intervention areas respectively experienced stillbirths. Similarly, about a quarter of the women said that they had at least one newborn death in the past. Only about a quarter of the women from both groups said that they were counseled by an antenatal care provider about protection against malaria and the commonest topic on which the women in the control and intervention groups received any instruction was indoor residual spray, 27% and 19% respectively. 32 percent women in control and 21% in intervention group identified health workers as the most common source of information about Malaria. Most women in both groups were aware that the malaria was caused by the mosquitoes (Table- 1).
Table 1: Baseline characteristics and information about malaria among control and intervention groups in the study
Variables
|
Control group (n=100)
|
Intervention group (n=100)
|
p-value
|
Age
|
≤25 years
|
22 (22%)
|
39 (39%)
|
0.029*
|
26-30
|
53 (53%)
|
39 (39%)
|
31 and above
|
25 (25%)
|
22 (22%)
|
Education
|
Uneducated
|
62 (62%)
|
83 (83%)
|
0.001*
|
Primary
|
16 (16%)
|
13 (13%)
|
Any Other Type of Education
|
22 (22%)
|
4 (4%)
|
Number of living children
|
1 – 2
|
17 (17%)
|
10 (10%)
|
0.111
|
3 – 4
|
54 (54%)
|
63 (63%)
|
5 – 6
|
9 (9%)
|
15 (15%)
|
7 – 9
|
20 (20%)
|
12 (12%)
|
Age at marriage
|
15,16
|
12 (12%)
|
11 (11%)
|
0.073
|
17
|
18 (18%)
|
34 (34%)
|
18
|
43 (43%)
|
36 (36%)
|
19-22
|
27 (27%)
|
19 (19%)
|
Type of Household
|
Mud house
|
79 (79%)
|
82 (82%)
|
0.592
|
Brick house
|
21 (21%)
|
18 (18%)
|
Number of Rooms
|
1-2
|
30 (30%)
|
21 (21%)
|
0.144
|
3-4
|
70 (70%)
|
79 (79%)
|
Owns a mobile phone
|
Yes
|
54 (54%)
|
21 (21%)
|
0.001*
|
No
|
46 (46%)
|
79 (79%)
|
Source of drinking water
|
A Well outside home
|
71 (71%)
|
49 (49%)
|
0.001*
|
A Well Inside home
|
29 (29%)
|
51 (51%)
|
Type of latrine
|
Open
|
51 (51%)
|
26 (26%)
|
0.001*
|
Pit Latrine
|
49 (49%)
|
74 (74%)
|
Mode of sewage drainage in house
|
Open Sewers
|
64 (64%)
|
33 (33%)
|
0.001*
|
Underground Sewers
|
2 (2%)
|
25 (25%)
|
In open Pond
|
34 (34%)
|
42 (42%)
|
Income (PKR)
|
5000
|
37 (37%)
|
76 (76%)
|
0.001*
|
6000-10000
|
48 (48%)
|
22 (22%)
|
11000-15000
|
15 (15%)
|
2 (2%)
|
Previous stillbirth (28 weeks)
|
Yes
|
35 (35%)
|
20 (20%)
|
0.018*
|
No
|
65 (65%)
|
80 (80%)
|
Previous newborn death
|
Yes
|
26 (26%)
|
18 (18%)
|
0.172
|
No
|
74 (74%)
|
82 (82%)
|
ANC counseling on malaria
|
Yes
|
35 (35%)
|
24 (24%)
|
0.088
|
No
|
65 (65%)
|
76 (76%)
|
Counseling topics
|
Use LLINs
|
4 (4%)
|
3 (3%)
|
0.925
|
Indoor Spray
|
27 (27%)
|
19 (19%)
|
Take preventive medicine
|
4 (4%)
|
2 (2%)
|
Malaria during any previous pregnancy
|
Yes
|
15 (15%)
|
29 (29%)
|
0.017*
|
No
|
85 (85%)
|
71 (71%)
|
Malaria during the current pregnancy
|
Yes
|
2 (2%)
|
1 (1%)
|
0.561
|
No
|
98 (98%)
|
99 (99%)
|
Ever heard about Malaria
|
Yes
|
34 (34%)
|
23 (23%)
|
0.085
|
No
|
66 (66%)
|
77 (77%)
|
Source of information about Malaria
|
Health Worker
|
32 (32%)
|
21 (21%)
|
0.683
|
Other
|
2 (2%)
|
2 2(%)
|
*Significant (p=<0.05)
Descriptive statistics were calculated for each knowledge and use of LLINs item on both intervention and control groups before the intervention to explore trends regarding use of LLINs between the two groups before and after intervention (Table 2). The women’s perception that malaria was a harmful disease increased from 75% to 97% after the intervention, whereas in the control arm this change was only 10 percent points from 30% to 40%. The use of LLINs has increased in the intervention group at post intervention assessment due to health education from 10-30%; while in the control group only 1-3% has improved. Most of the study population has increased their knowledge on mode of transmission from (75-97%) about malaria in intervention group. Most of the participant heard about the mosquito nets after the intervention (58-100%) and their ownership regarding mosquito nets has increased up to 76% after intervention (<0.05). The Lady health workers were the most prominent source of obtaining malaria information and it significantly increased in intervention group (<0.05). LLINs use is important in prevention of malaria both in mothers and child and it has increases substantially after the intervention (<0.05). Generally, community knowledge regarding malaria prevention was high. Mosquito nets use during the pregnancy (practices), importance of LLINs during pregnancy (Knowledge) and its importance (attitude) has been increased in both groups however significant change (<0.05) was observed in intervention group (31-73%). Participants have shown a positive improvement while using the indoor mosquito spray after intervention (<0.05). Most of the respondents reported that they used LLINs last night while sleeping; the frequency of LLINs users has also increased after intervention (<0.05). However, no significant differences were found between the groups at baseline except source of information, type of LLINs available and its importance (p >0.05).
Table 2: Comparison of change in the use LLINs and other malaria preventive measures (before and after, and between control and intervention groups)
Variables
|
Control (n=100)
|
Intervention (n=100)
|
Before
|
After
|
p value
|
Before
|
After
|
p value
|
|
Knowledge
|
|
Transmission
|
Insect bite
|
21 (21%)
|
17 (17%)
|
0.106
|
25 (25%)
|
3 (3%)
|
0.765
|
|
Mosquito bite
|
79 (79%)
|
83 (83%)
|
75 (75%)
|
97 (97%)
|
|
Symptoms
|
Fever
|
69 (69%)
|
66 (66%)
|
0.314
|
61 (61%)
|
77 (77%)
|
0.286
|
|
Headache
|
31 (31%)
|
34 (34%)
|
26 (26%)
|
23 (23%)
|
|
Severity
|
Yes
|
30 (30%)
|
40 (40%)
|
0.210
|
75 (75%)
|
97 (97%)
|
0.002*
|
|
No
|
70 (70%)
|
60 (60%)
|
25 (25%)
|
3 (3%)
|
|
Complications
|
Fever
|
69 (69%)
|
66 (66%)
|
0.314
|
61 (61%)
|
77 (77%)
|
0.286
|
|
Vomiting
|
31 (31%)
|
34 (34%)
|
39 (39%)
|
23 (23%)
|
|
Prevention
|
By using LLINs
|
46 (46%)
|
44 (44%)
|
0.255
|
31 (31%)
|
87 (87%)
|
0.893
|
|
Spray
|
54 (54%)
|
46 (46%)
|
69 (69%)
|
13 (13%)
|
|
Heard about LLINs
|
Yes
|
61 (61%)
|
48 (48%)
|
0.065
|
58 (58%)
|
100 (100%)
|
<0.001*
|
|
No
|
39 (39%)
|
52 (52%)
|
42 (42%)
|
0
|
|
LLINs use
|
Prevents newborn
|
46 (46%)
|
50 (50%)
|
0.093
|
28 (28%)
|
6 (6%)
|
0.053*
|
|
Prevents mother
|
54 (54%)
|
50 (50%)
|
72 (72%)
|
94 (94%)
|
|
Use LLINs prevents malaria
|
Yes
|
35 (35%)
|
40 (40%)
|
0.465
|
100 (100%)
|
100 (100%)
|
<0.001*
|
|
No
|
65 (65%)
|
60 (60%)
|
0
|
0
|
|
Use of LLINs
|
|
LLINs presence
|
Yes
|
81 (81%)
|
70 (70%)
|
0.091
|
85 (85%)
|
97 (97%)
|
0.003*
|
|
No
|
19 (19%)
|
30 (30%)
|
15 (15%)
|
3 (3%)
|
|
Use LLINs in pregnancy
|
Yes
|
35 (35%)
|
39 (39%)
|
0.474
|
31 (31%)
|
73 (73%)
|
<0.001*
|
|
No
|
65 (65%)
|
61 (61%)
|
69 (69%)
|
27 (27%)
|
|
LLINs use are important in pregnancy
|
Yes
|
35 (35%)
|
39 (39%)
|
0.474
|
31 (31%)
|
73 (73%)
|
<0.001*
|
|
No
|
65 (65%)
|
61 (61%)
|
69 (69%)
|
27 (27%)
|
|
Use LLINs last night
|
Yes
|
35 (35%)
|
36 (36%)
|
0.883
|
31 (31%)
|
96 (96%)
|
<0.001*
|
|
No
|
65 (65%)
|
64 (64%)
|
69 (69%)
|
4 (4%)
|
|
Use spray in last 3months
|
Yes
|
35 (35%)
|
33 (33%)
|
0.765
|
31 (31%)
|
81 (81%)
|
<0.001*
|
|
No
|
65 (65%)
|
67 (67%)
|
69 (69%)
|
19 (19%)
|
|
*Significant (p=<0.05)
DID is usually implemented as an interaction term between time and treatment group dummy variables in a regression model. The coefficient of the treatment variable (intervention), is the estimated mean difference in outcome (Knowledge & use of LLINs) between the treatment and control groups prior to the intervention; it represents whatever "baseline" differences existed between the groups before the intervention was applied to the control group. At Baseline, the coefficient of intervention is 0.43 (knowledge) and -0.02 (use of LLINs), however it is not significant (Table 3).
The time trend (post intervention) is the expected mean change in outcome from before to after the onset of the intervention era among the control group. It reflects, if you will, the pure effect of the passage of time in the absence of the actual intervention. The coefficient of time trend (post-intervention) is 0.57 (knowledge) and it is significant at 5% level of significance. Similarly, the coefficient of time trend (post-intervention) for use of LLINs is 0.57, which is significant at 5% level of significance (Table 3).
The interaction term by itself is the difference in differences estimator. The coefficient for interaction term is the differences-in-differences estimator. The effect is significant at 1% level of significance with the treatment having a positive effect.
Table 3: Difference in differences (DID) with time trend and interaction term
Variables
|
Model-1a
|
Model-2b
|
Model-3c
|
Model-4d
|
Treatment
|
0.430
|
-0.020
|
0.106
|
-0.238
|
|
(0.276)
|
(0.221)
|
(0.364)
|
(0.277)
|
Time (Post-intervention)
|
0.570**
|
0.320
|
0.570**
|
0.320
|
|
(0.276)
|
(0.221)
|
(0.284)
|
(0.229)
|
Interaction term
|
4.170***
|
3.360***
|
4.170***
|
3.360***
|
|
(0.390)
|
(0.312)
|
(0.382)
|
(0.309)
|
Confounders
|
No
|
No
|
Yes
|
Yes
|
R square
|
0.540
|
0.500
|
0.570
|
0.530
|
Prob > F
|
0.000
|
0.000
|
0.000
|
0.000
|
Confounders: age, education, income, etc
Standard errors in parentheses; * p<0.1, ** p<0.05, *** p<0.01
a = Model 1: Estimation of Knowledge without confounders
b = Model 2: Estimation of Use of LLINs without confounders
c = Model 3: Estimation of Knowledge with confounders
d = Model 4: Estimation of Use of LLINs with confounders
Results of Difference in Difference (DID) regression estimation with an interaction between time (Baseline vs. post intervention) and groups (Control & Intervention) were used to the estimate magnitude of the effect of intervention (Knowledge and use of LLINS change due to intervention by controlling time) and its statistical significance. The results (Table 4) showed that there were no significant differences between the mean knowledge and use of LLINs scores of the groups at baseline. However, the mean knowledge and use of LLINs scores increased significantly in the intervention group as compared to the control group after intervention. Therefore, it can be inferred that the estimated difference-in-difference value of 4.170 (p <0.01) represents an increase in scores of knowledge in the intervention group as compared with control after intervention. Similarly, it is estimated that increase in use of LLINs score after intervention is represented by difference-in-difference value of 3.360 (p <0.01). The analysis was also done by controlling for confounders and it showed similar results. Thus, it can be concluded that the scores of knowledge and use of LLINs improved in the intervention group, which is due to the effect of intervention.
Table 4: Difference in Differences (DID) Estimation with and without confounders
Difference in Differences (DID) without confounders
|
|
Baseline (BL)
|
Post Intervention (PI)
|
|
Outcome variables
|
Control
|
Intervention
|
Diff (BL)
|
Control
|
Intervention
|
Diff (EL)
|
Diff-In-Diff
|
|
Knowledge
|
5.250
|
5.680
|
0.430
|
5.820
|
10.420
|
4.600
|
4.170
|
|
SE**
|
|
|
0.312
|
|
|
0.235
|
0.390
|
|
t value
|
|
|
1.380
|
|
|
19.57
|
10.68
|
|
p value
|
|
|
0.169
|
|
|
0.000***
|
0.000***
|
|
R square
|
0.54
|
|
|
|
|
|
|
|
Use of LLINs
|
4.530
|
4.510
|
-0.020
|
4.850
|
8.190
|
3.340
|
3.360
|
|
SE**
|
|
|
0.245
|
|
|
0.194
|
0.313
|
|
t value
|
|
|
-0.08
|
|
|
17.18
|
10.75
|
|
p value
|
|
|
0.935
|
|
|
0.000***
|
0.000***
|
|
R square
|
0.59
|
|
|
|
|
|
|
|
Difference in Differences (DID) with confounders
|
Knowledge
|
5.605
|
5.712
|
0.107
|
6.175
|
10.452
|
4.277
|
4.170
|
|
SE
|
|
|
0.309
|
|
|
0.309
|
0.383 |
|
|
t value
|
|
|
0.35 0
|
|
|
13.82
|
10.90
|
|
p value
|
|
|
0.730
|
|
|
0.000***
|
0.000***
|
|
R square
|
0.58
|
|
|
|
|
|
|
|
Confounders
|
Yes
|
|
|
|
|
|
|
|
Use of LLINs
|
2.785
|
2.546
|
-0.239
|
3.105
|
6.226
|
3.121
|
3.360
|
|
SE
|
|
|
0.250
|
|
|
0.250 |
|
0.309
|
|
t value
|
|
|
-0.95
|
|
|
12.48
|
10.87
|
|
p value
|
|
|
0.341
|
|
|
0.000***
|
0.000***
|
|
R square
|
0.53
|
|
|
|
|
|
|
|
Confounders
|
Yes
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Confounders: age, education, income, etc
*Means and SE are estimated by linear regression
**Robust Std. Errors
*** p<0.01