## Cost - effectiveness of



## prevention: Community - based interventions to control and prevent Lyme disease 

### Martin Meltzer, Ph.D., MS Division of Preparedness & Emerging Infections (DPEI) Centers for Disease Control and Prevention (CDC)

E-mail: qzm4@cdc.gov

# Disclaimer This presentation represents the work of the author and does not necessarily represent the policy or opinion of the CDC or DHHS.

# What is . . .

The cost-effectiveness of community-based 

### Lyme disease control measures?

# ANSWER:  Not sure  No readily accessible published studies. 

###  WHY no available answer?  Missing/ non-existent data

# What is cost- effectiveness?  Expressed as $/ per unit health outcome  E.g., $/ case averted 

###  Cost per case = $ Intervention - $ saved

Cases averted

# REMEMEBR Cost-Effectiveness = Cost Savings What is: a ”reasonable” threshold? 

### the maximum “allowable” $/ case averted? 

## “Cost-Effectiveness” is SUBJECTIVE term

# FURTHER
Cost Savings = “Must Do”

## 4 data “buckets” needed for a good 

## cost- effectiveness study  Epidemiology and clinical  Who, when where, what happens  Cost of clinical illnesses and outcomes  Interventions  What, how well work, where, side effects?  Must have a comparator  Cost of interventions  Must include $ of treating side effects

### Epidemiological data: Risk clinical case

Confirmed cases / 100,000 population

Source: http://www.cdc.gov/ncidod/dvbid/lyme/ld_IncidenceRatesbyState20052009.htm

State 2007 2008 2009 Alabama 0.3 0.1 0.1 Alaska 1.5 0.9 1.0 Arizona 0.0 0.0 0.0 Arkansas 0.0 0.0 0.0 California 0.2 0.2 0.3 Colorado 0.0 0.0 0.0 Connecticut 87.3 78.2 78.2 Delaware 82.7 88.4 111.2 District of Columbia 19.7 12.0 8.8 Florida 0.2 0.4 0.4 Michigan 0.5 0.8 0.8

### Epidemiological data: Risk clinical case

Source: http://www.cdc.gov/ncidod/dvbid/lyme/ld_Incidence.htm

## Epidemiological data

Smith et al. Public Hlth Report 2001 (supp 1).

## Epidemiological data  Risk factors:  Age: 10
- 19 years; and 50+ years of age  Rural > urban (3 times more)  Single homes, homes with woods, <100 ft to woods  Gardening + 4 hrs/ week  Other factors: not risk 

###  MUST place risk in context  Geography, season, exact activity, ecology, etc. Source: Smith et al. Public Hlth Report 2001 (supp 1).Reported Lyme Disease Cases by Age Category, United States, 1992 - 2006Clinical Features of Lyme Disease Cases Reported to CDC, United States, 1992 - 2006Erythema migrans

Arthritis Neurological Cardiac Change in Frequency of Clinical Features, United States, 1992 - 2006

### Bucket #2: Cost of case

Note: $ costs in 2000 $ Source: Zhang et al. Emerg Infect Dis 2006

### Bucket #2: Cost of case: outcome tree

Note: $ costs in 2000 $ Source: Zhang et al. Emerg Infect Dis 2006

### Bucket #2: Cost of confirmed case 

###  For each confirmed LD patient  $2,970 direct medical cost  $4,762 indirect medical cost, non

-medical cost and productivity loss 

###  Economic burden of LD in U.S. (2000 $)  184 million dollars  Conservative and underestimated

Note: $ costs in 2000 $ Source: Zhang et al. Emerg Infect Dis 2006

### Bucket #3: Interventions 

###  Vaccination  Control tick hosts  Population reduction or exclusion 

###  Personal protection  Control ticks  On hosts or on ground

### Interventions: vaccine: analysis

Source: Meltzer et al. Emerg infect Dis 1999Source: Meltzer et al. Emerg infect Dis 1999

### Conclusions: Vaccine: Cost - effectiveness 

###  Public health policy implications Value in targeting by risk of LD Value in increasing probability of correct eraly diagnosis and successful treatment 

###  Similar conclusions from:  Hsia et al. Arthritis & Rheumatism, 2002.White footed mouse White tailed deer

Natural hosts and reservoirs of B. burgdoferi 

# Interventions: Control hosts

### Deer Reduction: NJ

Source: Jordan et al, J. Med Entomol, 2007

### Personal protection: reduced risk: CT: 

###  Protective clothing: 

## 40% (95% C.I.: 30 – 50%)  Tick repellants: 

## 20% (10% - 40%)  Checking for ticks: 

## 0% Not effective  Spraying property: 

## 0% Not effective Note: case control: CT. 709 cases Source: Vazquez et al Emerg Infect Dis 2008

## Personal protection: In -yard  Bathed within 2 hrs: 

### 40% (95% C.I.: 22% – 77%)  Tick repellants: 

### 41% (N/A - 65%)  Checking for ticks: 

### 45% (6% - 68%)  Fencing yard : 

## 46% (10% – 66%)  All else (spraying, landscape, etc.): 

## No effect
Note: Case control: CT.: 364 cases enrolled Source: Connally et al. Am J Prevent Med 2009

### Self - Medicating applicators: History: Duncan Applicators – 1970s onward

Source: http://www.wpazambia.com/ForSaleSpecialOffers/DuncanApplicator.html

# Self - medicating applicators

# Self - medicating applicators

Source; Norval et. al: Self medicating applicator for controlling pests on animals. U.S. Patent 5,357,902, Oct 25, 1994.

## Impact of applicators:

White - tailed deer Group Ticks* /

deer S.E. Treatment: pesticide 3.4 1.1 

### Control: mineral oil 10.8** 3.0 *Ticks: Ixodes scapularis ** P < 0.0001

Source: Sonenshine et al Med Vet Entom 1996:10:1490154

## Impact of applicators:

Nymphs: 5 sites

Source: Brei et al. Vect Borne Zoo Dis, 2009

### Potential problem: Alternative hosts  Mice not primary host for ticks nor primary reservoir for B. burgdorferi ss,  Mice feed 10% all ticks ; 25% B. burgdorferi-infected ticks 

###  Inconspicuous shrews feed 35% all ticks; 55% infected ticks 

###  May require interventions for multiple species Source: Dustin et al. Proc R Soc B, 2008

## Applicators: What is missing? No. human cases



## Number of ticks

(Infesting hosts, infected, questing, etc.)



### Response A Response B 

## ORIxodes scapularis

Source: CDC Public Health Image Library http://phil.cdc.gov/phil/home.asp 

### In other words: Don’t need this . . .Source: CDC Public Health Image Library http://phil.cdc.gov/phil/home.asp 

### Need this: Impact on risk of cases

## Bucket #4: $ of interventions 

##  $ vaccination - have/ had  $ costs of other interventions  Appears to be mostly lacking

## Bucket #4: Stated support

Source: Gould et al, Vect Borne Zoo Dis, 2008

## Bucket #4: Beware  What people say and what they do  Often 2 very separate things  Support of community intervention  Depends upon perceptions  Can you “see” cases? 

###  Compliance over time  Incredibly big issue  “poorly” measured – if at all.

### Conclusions: Cost - effectiveness of community based interventions 

##  Lack adequate data  Relationship: tick reduction and cases 

###  Effectiveness over time  Compliance over time – usually drops 

###  Costs of interventions  Sustained – can’t stop 

###  Costs of side effects of interventions

### Conclusions: Cost - effectiveness of community based interventions 

##  What is needed:  Field trial(s)  Large  Measure impact on cases  Run for “some time”  E.g., 3 – 5 years 

###  Measure changes in community acceptance  More than 1 site  Measure – different risks, attitudes, etc.