Participant Flow Diagram & Exclusions

Geographical Locations and Clustering

As defined in the inclusion criteria, participants were recruited from Bengaluru district. Two subjects who acquired the habit in Bangalore but then shifted the residence to other districts of the Karnataka have been retained in the analysis.

The figures below show the general location of all participants and that the biggest cluster of patients are from near NIMHANS.

Socio-demographic Characteristics

A total of 272 participants were recruited for this study. However, two entries in community arm were later identified as duplicates where the same patient gave different name. Only one of the entries are retained leaving us with 270 unique participants.
As described in the methodology, we had marked cases as suspicious when we were not able to ascertain if they were PWIDs one way or another. 8 cases are retained in the analysis. For HCV seroprevalence results we report results with and without including them.

The participants belong to two distinct groups:

  1. Convenience Sample (recruited at NIMHANS).
  2. Community Sample (recruited via peer-referrals and linkages).

The following table shows the basic demographic details of the participants:

Demographic profile of patients

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Age

26 (24, 30)

24 (22, 26)

<0.001

Gender

>0.9

Male

93 (100%)

176 (99%)

Female

0 (0%)

1 (0.6%)

Years of education

8 (7, 10)

9 (7, 10)

0.001

Occupation as classified in nfhs

0.4

Skilled and unskilled manual

65 (70%)

109 (62%)

Not working

9 (9.7%)

26 (15%)

Sales

9 (9.7%)

24 (14%)

Services / household and domestic

9 (9.7%)

11 (6.2%)

Professional / technical / managerial

1 (1.1%)

6 (3.4%)

Clerical

0 (0%)

1 (0.6%)

Is a gig worker?

23 (25%)

54 (31%)

0.3

Kuppuswamy socio-economic status class

0.3

Upper middle class

42 (45%)

68 (38%)

Middle class

35 (38%)

71 (40%)

Lower middle class

9 (9.7%)

29 (16%)

Upper class

6 (6.5%)

9 (5.1%)

Lower class

1 (1.1%)

0 (0%)

1Median (Q1, Q3); n (%)

2Wilcoxon rank sum test; Fisher's exact test; Pearson's Chi-squared test

Gig worker as defined in the Karnataka Draft Bill

Amongst the patients recruited from the hospital (convenience sample), most came to know about treatment services via thier peers (Figure below).

Detailed Description of Socio-economic status

Although, the Kuppuswamy scale shows most patients to be in upper middle socio-economic status we did a finer analysis with reported monthly income and number of members in the household.

Comparison of socioeconomic status of participants

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Self reported monthly earning of the household

9680 (7090, 12550)

7950 (7060, 12160)

0.4

What is the total number of people in the household?

4 (3, 5)

4 (3, 5)

0.013

Calculated monthly per capita income

2337 (1800, 3517)

2033 (1512, 3205)

0.047

Education of head of the family

0.046

Middle school certificate

26 (28%)

53 (30%)

High school certificate

21 (23%)

44 (25%)

Illiterate

23 (25%)

23 (13%)

Primary school certificate

8 (8.6%)

35 (20%)

Intermediate or post-high-school diploma

9 (9.7%)

13 (7.3%)

Graduate or post-graduate

5 (5.4%)

4 (2.3%)

Professional degree

1 (1.1%)

5 (2.8%)

Occupation of the head of the family

0.4

Skilled worker

42 (45%)

69 (39%)

Semi-skilled worker

22 (24%)

56 (32%)

Clerical/ shop owner/ farmer

9 (9.7%)

21 (12%)

Unskilled worker

13 (14%)

14 (7.9%)

Professional

5 (5.4%)

7 (4.0%)

Unemployed

2 (2.2%)

6 (3.4%)

Semi-professional

0 (0%)

4 (2.3%)

1Median (Q1, Q3); n (%)

2Wilcoxon rank sum test; Fisher's Exact Test for Count Data with simulated p-value
  (based on 2000 replicates)

Income in INR.

Per capita income equally distributes the family income not by gender or age

  • There are no significant differences between the two types of participants.

  • The reported education of the head of the family is rarely beyond high school.

Per-capita income and income percentiles

It is difficult to interpret monthly earnings without a reference point. It is more informative to compare the per-capita income of these households with the rest of the population. An established method of doing this (as explained in methodology) is to see which percentile do these patients belong to based on their reported income.

Most of the patients belong to the lowest centiles with respect to per capita income as can be seen from the figure below. For illustration, 65% of the respondents earned less than 90 % of the population.

Comparison of Household Level Variables with NFHS-5 Data

To better situate these patients with respect to the general standard of living in Bangalore city, we obtained raw data from NFHS-5 via Department of Health Services, Government of the United States.
We compare key variables related to assets and amenities in our sample with that of the general population in Bangalore city.

Comparison of Ownership of various items between study participants and a representative household in Bangalore urban district.

Characteristic

1. Study Participants
N = 1821

2. NFHS-5
N = 7541

p-value2

Household has an air conditioner or cooler?

1 (0.5%)

208 (28%)

<0.001

Household has a water pump?

2 (1.1%)

76 (10%)

<0.001

Household has a computer?

15 (8.2%)

179 (24%)

<0.001

Anyone in the household owns the land of residence or any other residential land?

91 (50%)

195 (26%)

<0.001

Household has a car?

8 (4.4%)

142 (19%)

<0.001

Household has electricity?

180 (99%)

743 (99%)

0.7

Household has a radio?

0 (0%)

32 (4.3%)

0.004

Household has a black and white television?

1 (0.5%)

13 (1.7%)

0.3

Household has a colour television?

175 (96%)

699 (93%)

0.10

Household has a mattress?

180 (99%)

695 (92%)

0.001

Household has a pressure cooker?

181 (99%)

721 (96%)

0.013

Household has a chair?

178 (98%)

716 (95%)

0.10

Household has a cot or bed?

176 (97%)

693 (92%)

0.024

Household has a table?

167 (92%)

637 (85%)

0.012

Household has an electric fan?

171 (94%)

721 (96%)

0.3

Household has a sewing machine?

1 (0.5%)

160 (21%)

<0.001

Household has internet access?

126 (69%)

503 (67%)

0.5

Household has a washing machine?

93 (51%)

390 (52%)

0.9

Household has a refrigerator?

152 (84%)

555 (74%)

0.006

Household has a bicycle?

4 (2.2%)

220 (29%)

<0.001

Household has a motorcycle or scooter?

126 (69%)

575 (76%)

0.051

Household has a landline telephone?

1 (0.5%)

59 (7.8%)

<0.001

Household has a mobile telephone?

174 (96%)

726 (96%)

0.7

Household owns agricultural land?

12 (6.6%)

51 (6.8%)

>0.9

Household owns any livestock?

3 (1.6%)

15 (1.9%)

0.8

Anyone in the household has a bank account?

179 (98%)

718 (95%)

0.059

1n (%)

2Pearson's X^2: Rao & Scott adjustment

The NFHS data is weighted with distric level weights. Weights for study participants is 1.

Data Acknowledgement: DHS Program USAID

This comparison is interesting. While certain items traditionally mapped by NFHS like radio, internet access, landline may be less relevant in urban settings. Ownership of costly consumer durables like AC, car and computer is definitely lower in our sample. On the other hand posession of land which is a marker of wealth is higher in our sample.

We next compare the two samples on basic amenities and housing.

Comparison of household size, religion and amenities between study participants and a representative household in Bangalore urban district.

Characteristic

1. Study Participants
N = 1821

2. NFHS-5
N = 7541

p-value2

What is the total number of people in the household?

4.00 (3.00, 5.00)

4.00 (3.00, 4.00)

<0.001

Number of sleeping rooms (capped at 4).

<0.001

1

62 (34%)

10 (1.3%)

2

99 (54%)

245 (32%)

3

21 (12%)

394 (52%)

4+

0 (0%)

105 (14%)

Number of persons per sleeping room (capped at 4).

<0.001

1

4 (2.2%)

299 (40%)

2

61 (34%)

392 (52%)

3

82 (45%)

49 (6.5%)

4+

35 (19%)

14 (1.8%)

Religion of the household

<0.001

christian

8 (4.4%)

30 (4.0%)

hindu

47 (26%)

650 (86%)

muslim

127 (70%)

67 (8.9%)

other

0 (0%)

6 (0.9%)

Household uses lpg or natural gas for cooking?

182 (100%)

728 (97%)

0.013

Type of floor in the house

0.14

Finished Material

182 (100%)

745 (99%)

Unfinished Material

0 (0%)

9 (1.2%)

Type of wall in the house

<0.001

Finished Material

181 (99%)

644 (85%)

Unfinished Material

1 (0.5%)

110 (15%)

Type of roof in the house

0.015

Finished Material

182 (100%)

729 (97%)

Unfinished Material

0 (0%)

25 (3.3%)

1Median (Q1, Q3); n (%)

2Design-based KruskalWallis test; Pearson's X^2: Rao & Scott adjustment

The NFHS data is weighted with distric level weights. Weights for study participants is 1.

Data Acknowledgement: DHS Program USAID

  • It is clear that the houses of study participants are in general smaller than an average household. While, less than 40% of representative households have less than 3 rooms for sleeping, more than 80% of study participants lived in a house with 1 or 2 rooms.

  • This limited space is shared by more members in study participants’ houses as compared to a representative household.

  • The distribution of religion in the study group also differs significantly from the general population as surveyed two years back.

  • On the other hand, the households of study participants are no different or even better in amenities like cooking fuel and type of house construction.

  • The difference in household size is difficult to interpret due to overlapping medians and first quantile. We therefore, examined the distribution to understand this.

We can see that this difference is mainly due to a high proportion of study participants having 5 or more household members as compared to the representative household based on NFHS 5 data.

Comparison of Individual Level Variables with NFHS-5 Data

Comparison of age and education (males only)

Characteristic

1. Study Participants
N = 2721

2. NFHS-5
N = 7041

p-value2

Age

24 (22, 27)

33 (26, 38)

<0.001

Years of education

9.0 (7.0, 10.0)

12.0 (10.0, 15.0)

<0.001

Unknown

1

0

1Median (Q1, Q3)

2Design-based KruskalWallis test

The NFHS data is weighted with distric level weights. Weights for study participants is 1.

Only male respondents of age 18-45 years in NFHS-5 dataset are used to ensure comparability of samples

Data Acknowledgement: DHS Program USAID

  • Patients are significantly younger than the median adult male represented by NFHS-5 data.

  • On average they are also significantly and substantially (3 years difference) less educated than the median male of the city.

Neighbourhood Level Relative Wealth Index

As described in the methodology, RWI is a new and unitless measure and thus we first examined its relevance for the whole country. As seen in the figure below, at the country level the RWI is high in capital and large cities as compared to other areas. This distribution is in line with our expectation and thus we went on to analyse the RWI for Bangalore district.

At the city level, we see higher RWI values (on a scale of 0-1) in central buisiness district and other hubs of economic activity (Figure below).

However unlike comparison with NFHS median household we see no evidence of locality level deprivation in study participants. In the figure below we see that the residential address of most participants are in high RWI grid tiles.

Visually this finding is so apparent that we did not undertake comparison of median RWI’s of the participant’s localities with the median RWI of other tiles.

Neighbourhood Level Measures of Population Density and Overcrowding

As described in the methodology, we first aggregated the number of persons in square grids of 1 km side. This yields population density in persons per km2 of built-up area. Since, this is a relatively new measure, similar to RWI we first examined the data at the country level.

As can be seen in the figure, at the state level UP, Bihar, West Bengal and Kerala have an overall higher pop. density than most other states. This is in line with the population projections from various sources. Furthermore, major urbanisation centres like Delhi, Bangalore, Mumbai and almost all state capitals show highest population densities.

However, since there is no established index of overcrowding using number of persons per km square of built-up area we have to look at this data in a relative fashion. We have used percentile ranking to better discern areas where pop. density is substantially higher than the rest of the country. For illustration, we have 2228908 (22 lakh) individual grid cells, each being a 1 km2 peice of land with some built up structures. If we arrange them in ascending order of pop.density we can rank them from the least populated to most populated. Finally, we can calculate the percentile rank by dividing the rank with the number of grid cells. This leads to an easily interpretable metric for comparison.

In the figure below we see that extremely high values are seen only in some urban centres. We then examined the data for Bangalore.

It is striking to note that Bengaluru Urban district has one of the most densely populated areas in the country. We see large areas that are in the top 0.01 percent in terms of the number of persons per sq. km of built-up structures.

When we examine the residential address of participants with respect to the pop. density it is visible that many of them come from the most densely populated areas - not only in the city but in the whole country (Figure below).

Nevertheless, it is not clear if the patients experience statistically significant levels of overcrowding than an average person in Bangalore. To test this hypothesis we compare the pop. density at the residential addresses of participants with the overall pop. density distribution in Bangalore using KS test as detailed in methodology.

We find that a higher proportion of study participants lived in areas with higher pop. density than would be expected if they were a random subsample from the population of Bangalore. This difference is significant and the magnitude can be judged from the medians and quantiles given below.

Comparison of pop.density at participants residence with that of whole bangalore

Characteristic

All 1km.sq grid cells in Bangalore
N = 45971

Grid cells with study participants residence
N = 2671

p-value2

Population Density

537.0 (240.0, 1339.0)

1487.0 (1231.0, 26093.0)

<0.001

1Median (Q1, Q3)

2Wilcoxon rank sum test

Pop.density = persons/km.sq of built-up area

Substance Use Profile

Current and lifetime use of substances

Tables below summarises the lifetime and current use of substances in the sample.

Life time substance use comparison

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Tobacco products (cigarettes, bidis, gutkha, zarda etc)

93 (100%)

177 (100%)

Alcoholic beverage (rum, whisky, beer, tadi, sarai, tharra)

55 (59%)

63 (36%)

<0.001

Cannabis (ganja, bhang, charas)

93 (100%)

144 (81%)

<0.001

Opioids (heroin, chitta, tidigesic, fortwin, ultracet, tramazac, tydol, cough syrup)

93 (100%)

177 (100%)

Sedatives (nitravat, n10, valium, alprax, restyl, zolpid, traika)

39 (42%)

56 (32%)

0.092

Amphetamine type stimulants (md, crystal, ice, ecstasy)

71 (76%)

90 (51%)

<0.001

Cocaine (crack, coke)

7 (7.5%)

7 (4.0%)

0.3

Inhalants (correction fluid, whitener, dendrite, puncture fluid, paint thinner, solution, petrol)

6 (6.5%)

12 (6.8%)

>0.9

Hallucinogens (lsd, acid, stamp, k, ketamine, mushrooms)

5 (5.4%)

6 (3.4%)

0.5

1n (%)

2Pearson's Chi-squared test; Fisher's exact test

Current substance use (past 3 months) comparison

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Tobacco products (cigarettes, bidis, gutkha, zarda etc)

92 (99%)

177 (100%)

0.3

Alcoholic beverage (rum, whisky, beer, tadi, sarai, tharra)

45 (82%)

18 (29%)

<0.001

Cannabis (ganja, bhang, charas)

89 (96%)

70 (49%)

<0.001

Opioids (heroin, chitta, tidigesic, fortwin, ultracet, tramazac, tydol, cough syrup)

93 (100%)

177 (100%)

Sedatives (nitravat, n10, valium, alprax, restyl, zolpid, traika)

22 (56%)

11 (20%)

<0.001

Amphetamine type stimulants (md, crystal, ice, ecstasy)

60 (85%)

29 (32%)

<0.001

Cocaine (crack, coke)

2 (29%)

1 (14%)

>0.9

Inhalants (correction fluid, whitener, dendrite, puncture fluid, paint thinner, solution, petrol)

1 (17%)

0 (0%)

0.3

Hallucinogens (lsd, acid, stamp, k, ketamine, mushrooms)

1 (20%)

0 (0%)

0.5

1n (%)

2Fisher's exact test; Pearson's Chi-squared test

Life time substance use comparison

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Tobacco products (cigarettes, bidis, gutkha, zarda etc)

93 (100%)

177 (100%)

Alcoholic beverage (rum, whisky, beer, tadi, sarai, tharra)

55 (59%)

63 (36%)

<0.001

Cannabis (ganja, bhang, charas)

93 (100%)

144 (81%)

<0.001

Opioids (heroin, chitta, tidigesic, fortwin, ultracet, tramazac, tydol, cough syrup)

93 (100%)

177 (100%)

Sedatives (nitravat, n10, valium, alprax, restyl, zolpid, traika)

39 (42%)

56 (32%)

0.092

Amphetamine type stimulants (md, crystal, ice, ecstasy)

71 (76%)

90 (51%)

<0.001

Cocaine (crack, coke)

7 (7.5%)

7 (4.0%)

0.3

Inhalants (correction fluid, whitener, dendrite, puncture fluid, paint thinner, solution, petrol)

6 (6.5%)

12 (6.8%)

>0.9

Hallucinogens (lsd, acid, stamp, k, ketamine, mushrooms)

5 (5.4%)

6 (3.4%)

0.5

1n (%)

2Pearson's Chi-squared test; Fisher's exact test

ASSIST Substance Use Risk Scores

Comparison of substance use risk scores

Characteristic

Community
N = 931

Convenience
N = 1771

p-value2

Risk category: tobacco

0.3

High risk

0 (0%)

4 (2.3%)

Moderate risk

93 (100%)

173 (98%)

Risk category: alcohol

<0.001

High risk

1 (1.1%)

3 (1.7%)

Low risk

70 (75%)

169 (95%)

Moderate risk

22 (24%)

5 (2.8%)

Risk category: cannabis

<0.001

High risk

29 (31%)

10 (5.6%)

Low risk

9 (9.7%)

109 (62%)

Moderate risk

55 (59%)

58 (33%)

Risk category: cocaine

0.12

Low risk

91 (98%)

177 (100%)

Moderate risk

2 (2.2%)

0 (0%)

Risk category: opioids

<0.001

High risk

68 (73%)

177 (100%)

Moderate risk

25 (27%)

0 (0%)

Risk category: stimulants

<0.001

High risk

3 (3.2%)

1 (0.6%)

Low risk

49 (53%)

159 (90%)

Moderate risk

41 (44%)

17 (9.6%)

Risk category: hallucinogens

Low risk

93 (100%)

177 (100%)

Risk category: sedatives

<0.001

Low risk

81 (87%)

173 (98%)

Moderate risk

12 (13%)

4 (2.3%)

Risk category: inhalants

>0.9

Low risk

92 (99%)

174 (98%)

Moderate risk

1 (1.1%)

3 (1.7%)

1n (%)

2Fisher's exact test; Pearson's Chi-squared test

  • Problematic use of all classes of substances except opioids and tobacco is significantly and substantially higher in sample recruited from the community.

This difference is more clearly shown in the figure below where we compare the proportion of problematic use (ASSIST categories: mild risk and high risk) in the two samples.

Age at onset of Problematic Substance Use

When we compare the age at onset of problematic substance use for various classes, we see no significant differences between the two groups (Table below).

Comparison of age at onset of problematic substance use

Characteristic

N

Community1

Convenience1

p-value2

Age At Onset: Tobacco

270

16 (14, 18)

16 (14, 18)

0.3

Age At Onset: Cannabis

152

17 (15, 20)

17 (15, 18)

0.3

Age At Onset: Opioids

270

21 (19, 25)

20 (18, 23)

0.056

Age At Onset: Alcohol

31

20 (17, 24)

16 (15, 19)

0.051

Age At Onset: Stimulants

62

19 (18, 22)

19 (18, 20)

>0.9

Age At Onset: Sedatives

18

20 (18, 22)

15 (15, 16)

0.002

1Median (Q1, Q3)

2Wilcoxon rank sum test

Classes with n < 10 are not shown

Quantitative Description of Tapentadol Use

Stigma and Motivation to change

HCV - Awareness, Prevalence & Treatment Continuum

Treatment Experience & Outcome for Opioid Use Disorder

Qualitative Description of Tapentadol Use