Consumption of antibiotics before and after sales regulations in Chile,

Colombia and Venezuela

Juan Jose Herrera Patiño, Yared Santa-Ana-Tellez, , Anahi Dreser, Ralph Gonzales, Veronika J. Wirtz

Center for Health Systems Research &Center of Evaluation and Survey Research, National Institute of Public Health, Mexico

Background

• One of the main drivers of antimicrobial resistance is antibiotic consumption.

• To combat resistance the WHO has recently recommended that sales restrictions of antibiotics should be reinforced.

• Several middle-income countries have enforced sales restriction of antibiotics (AB) – Chile in 1999,

– Colombia in 2005

– Venezuela in 2006.

• Enforcement may have an impact on use of antibiotics, but little systematic evaluation of its effect over time.

Study aim and methodsTo analyze the change in consumption of antibiotics (AB) in Chile, Colombia and

Venezuela between 1997 and 2010.

Design: Interrupted time series analysis of systemic AB consumption for Chile, Colombia and Venezuela and one other LA country (Mexico) as control group between 1997 and 2010.

Setting: Market intelligence data of AB sales aggregated at national level

WHO ATC code J01 quarterly between 1997 and 2010.

Study Population: The total AB consumption and

Stratification by

a) broad-spectrum therapeutic groups:

quinolones, macrolides/ lincosamides and third generation cephalosporins.

b) narrow spectrum groups: penicillin, trimethoprim-sulfamethoxazole, and first and second generation cephalosporins.

Methods (cont.) Interrupted time series with control group

Outcome: AB sales aggregated by country, expressed in defined daily dose per 1,000 inhabitants per day (DDD).

Intervention: • Venezuela: sale regulation only included the broad spectrum groups

• Chile and Colombia: sale regulation for all AB

• Control country: no sales regulation implemented

Data analysis:

a) AB consumption change

b) Trend change

Variable Description

Y(t) Consumption of the antibiotic at time “t”

T Time since start of measurement (T=1, 2, 3, 4,

…)

P 0 = before the intervention; points after the

intervention (P= 1, 2, 3, …)

D 0=pre-intervention, 1= post-intervention

G G=1 country where the intervention took place,

G=0 no intervention

У(t)= β0 + β1T+ β2 D + β3 P+ β4G + β5GT+ β6 GD + β7GP + ε(t)

Results (1): Sales restrictions varied in impact on AB between intervention countries

0

2

4

6

8

10

12

14

16

18

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Chile

Colombia

Venezuela

Control

DD

D p

er 1

000

inha

bita

nts

per d

ay

Results (2): Chile with the greatest impact of sale restrictions on AB consumption

Country 1** 2*** 3+ 6++ 1 + +

ChileCoef. 0.074 -6.468 0.006 7.343 0.080

p 0.650 0.000 0.972 0.000

ColombiaCoef. -0.089 -0.097 0.075 -0.203 -0.014

P 0.000 0.738 0.005 0.804

VenezuelaCoef. 0.070 -0.107 0.774 -0.248 0.844

p 0.000 0.912 0.013 0.878

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

DDD

per 1

000 i

nhab

itant

s per

day

Penicillins

Tetracyclines

Sulphonamides& trimethoprim

Macrolides,lincosamidesandstreptogramins

Quinoloneantibacterials

Cephalosporins1st & 2ndgeneration

Cephalosporinsthirdgeneration

Results (3): Sales restriction had a small impact on penicillin consumption in Columbia

Results (4): no significant change in consumption in Venezuela after sales restriction

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

DDD

per 1

000 i

nhab

itant

s per

day

Penicillins

Macrolides,lincosamidesandstreptograminsSulphonamides& trimethoprim

Cephalosporins1st & 2ndgeneration

Tetracyclines

Quinoloneantibacterials

Cephlosporins3rd generation

Limitations

• Retail sales data does not represent the entire pharmaceutical market of the country

• Independent validation of data sources such as market intelligence data is relevant but not possible in many cases

• Quantitative analysis can not explain the causes for the different impact of the intervention but can help to generate hypothesis

• Decrease in AB consumption does not necessarily indicate more adequate use

Conclusions

• The sales restrictions of antibiotics in these three countries had different impact on the sales volume.

• Qualitative research is needed to analyze the underlying causes for the different effects of policies restricting sales of antibiotics.

• Continuous reinforcement of sales restrictions is necessary to have a prolonged impact.

Acknowledgements:

• IMS Health for data provision

• Jose Miguel Torres Gonzalez from Colegio de Mexico for provision of feedback on the statistical analysis

Conflicts of interest:

• Authors declare no conflicts of interest

Funding sources:

• This study was funded by the National Institute of Public Health (INSP), Mexico