We found little evidence of effectiveness of HRLAs for promotion of exercise/improved diets .
Conclusions Overall , there is limited evidence suggesting that HRLAs are cost-effective in terms of changing health-related knowledge , behaviours or health outcomes .
The evidence that does exist indicates that HRLAs are only cost-effective when they target behaviours likely to have a large impact on overall health-related quality of life .
Background Development of new peer or lay health-related lifestyle advisor ( HRLA ) roles is one response to the need to enhance public engagement in , and improve cost-effectiveness of , health improvement interventions .
This article synthesis es evidence on the cost-effectiveness of HRLA interventions aim ed at adults in developed countries , derived from the first systematic review of the effectiveness , cost-effectiveness , equity and acceptability of different types of HRLA role .
Cost-Effectiveness of Extending Screening Mammography Guidelines To Include Women 40 to 49 Years of Age
There is universal agreement [ 1 - 4 ] that women 50 to 69 years of age should undergo  screening mammography  because r and omized , controlled trials have shown that such screening reduces breast cancer mortality in this age group [ 5 , 6 ] . This consensus is bolstered by the results of cost-effectiveness analyses that consistently show that this benefit can be achieved at a reasonable cost [ 7 - 9 ] . In contrast , whether women 40 to 49 years of age should undergo screening mammography is controversial [ 10 - 15 ] . Pooled results of large r and omized , controlled trials have shown no mortality reduction in 40- to 49-year-old women after 7 to 9 years of screening [ 5 , 16 - 18 ] . However , a statistically significant reduction in breast cancer mortality becomes apparent 10 to 14 years after the initiation of screening [ 19 ] . Some authors have argued that this delayed benefit should not be ignored [ 11 ] . However , the reality of constrained health care re sources requires that any benefit from preventive services be achieved at a reasonable cost . Two recently published analyses [ 20 , 21 ] suggest that mammographic screening in younger women may be as cost-effective as screening in older women . The first analysis [ 20 ] calculated average cost-effectiveness by comparing a strategy of screening  40- to 69-year-old women with no screening . Most of the benefit achieved by using this strategy occurs when women are 50 to 69 years of age . Therefore , this analysis did not address whether it is cost-effective to screen women from 40 to 49 years of age in addition to screening them from 50 to 69 years of age . To determine whether the additional benefit obtained by extending screening mammography to women 40 to 49 years of age comes at a reasonable cost would require an incremental cost-effectiveness analysis [ 22 - 26 ] . The second analysis [ 21 ] used a simplified life-expectancy accounting method , did not discount costs or benefits , and associated screening mammography with unsubstantiated mortality reductions ( 30 % for the base case ) . Neither analysis [ 20 , 21 ] included an important aspect of the results of screening mammography trials in 40- to 49-year-old women : that is , no benefit occurs until 10 years after the initiation of screening . An earlier analysis [ 10 ] found screening mammography to be more expensive in women 40 to 49 years of age than in women 50 years of age and older . This previous analysis calculated incremental cost-effectiveness , discounted costs and benefits , and included an estimated delay between the onset of screening and the onset of a mortality benefit . Our analysis extends this work by including up date d pooled results of the r and omized , controlled trials [ 19 ] ; actual delay times before the onset of benefits ; and up date d costs of mammography and treatment of breast cancer . Methods Model We developed a Markov model [ 27 , 28 ] that compared the life expectancy of women undergoing different breast cancer screening strategies . Except for women in whom breast cancer was diagnosed at the initiation of screening , women were healthy at entry into the model . At the end of each 1-year cycle , women were in one of four health states : They remained healthy , developed breast cancer and remained alive , died of breast cancer , or died of another cause . The transition probabilities [ that is , the probabilities of developing breast cancer , dying of breast cancer , and dying of another cause ] were both age- and strategy -dependent . The base-case analysis compared three strategies : 1 ) no screening ; 2 ) screening biennially from 50 to 69 years of age ; and 3 ) screening every 18 months from 40 to 49 years of age , followed by screening biennially from 50 to 69 years of age . The rationale for these screening intervals is discussed below . We calculated the cost-effectiveness of screening in women 50 years of age and older by comparing the first strategy with the second strategy . To determine the incremental cost-effectiveness of screening in 40- to 49-year-old women , we compared the second and third strategies . Costs and benefits were discounted at a rate of 3 % per year for the base-case analysis [ 23 ] . Benefits Trials of screening mammography have shown no reduction in breast cancer mortality among screened women until several years after the initiation of screening [ 5 , 18 , 29 , 30 ] . Meta-analyses and one pooled analysis have shown that among 40- to 49-year-old women , the summary relative risk reduction in breast cancer mortality 7 to 9 years after the initiation of screening is about 1 , indicating no reduction in mortality [ 5 , 16 - 18 ] . Ten to 12 years after the initiation of screening , a nonsignificant trend toward reduced mortality is evident in the screened group ( Figure 1 , left ) [ 5 , 18 , 29 , 30 ] . Recently up date d results show a statistically significant 16 % reduction that occurs 10 to 14 years after the initiation of screening [ 19 ] . For women 50 to 69 years of age , there is an initial period of about 5 years that shows no benefit from screening ( Figure 1 , right ) [ 18 , 29 , 30 ] . Figure 1 . Cumulative breast cancer mortality in  screened  ( black circles ) compared with  nonscreened ( white circles ) women . Left . Right . In our model , for women who start screening at 50 years of age , a 27 % reduction in breast cancer mortality ( Table 1 ) [ 5 ] begins 5 years after the initiation of screening and continues until age 74 years . Although screening ends at 69 years of age , we assumed that women would continue to benefit for another 5 years because of early detection of breast cancer in the last years of screening . For women who begin screening at 40 years of age , a 16 % reduction in breast cancer mortality starts at age 50 years ; this reduction increases to 27 % at age 55 years . Table 1 . Information Used To Calculate Life Expectancy Screening Interval The screening interval in r and omized , controlled trials of screening mammography has varied from 12 to 33 months for women 50 years of age and older . Pooled results of the efficacy of mammography  stratified by length of screening interval do not differ for women in this age group [ 5 ] . From published results [ 5 ] , we determined a 28 % ( 95 % CI , 15 % to 31 % ) reduction in breast cancer mortality in women 50 years of age and older who were screened every 18 to 33 months and a 25 % ( CI , 1 % to 43 % ) reduction in those screened every 12 months . For the base-case analysis , we therefore chose to perform biennial screening in women 50 years of age and older because screening more often only increases cost without increasing the benefits of screening . For the base-case analysis , we used the pooled reduction in breast cancer mortality ( 27 % ) [ 5 ] from all r and omized , controlled trials to determine the cost-effectiveness of biennial screening in 50- to 69-year-old women ; in a sensitivity analysis , we determined the cost-effectiveness of annual screening . The screening interval in r and omized , controlled trials has varied from 12 to 24 months for women 40 to 49 years of age . Pooled results of the efficacy of screening mammography  stratified by length of screening interval did not show a statistically significant reduction in breast cancer mortality for 12-month or 18- to 24-month screening intervals [ 5 ] . As noted above , recently reported pooled results of all r and omized , controlled trials , which on average used a screening interval of 18 months , showed a statistically significant 16 % reduction in breast cancer mortality 10 to 14 years after the initiation of screening [ 19 ] . We therefore assumed that a 16 % reduction in breast cancer mortality would be achieved with screening done every 18 months . This screening interval is consistent with the guidelines of organizations [ 2 , 3 ] that recommend screening every 1 to 2 years for 40- to 49-year-old women . In sensitivity analyses , we calculated the cost-effectiveness of annual and biennial screening , assuming the same 16 % reduction in breast cancer mortality among screened women . Utilities Because there are few data on the utility that women place on life after treatment of breast cancer or the utility placed on living with metastatic breast cancer , we did not include utilities in the base-case analysis . Data from a small Australian study [ 33 ] ( which observed a utility of about 0.8 for life after treatment of breast cancer and a utility of about 0.3 for life with metastatic cancer ) are included in a sensitivity analysis to determine the extent to which cost per year of life saved might differ from cost per quality -adjusted life-year saved . Costs We included three costs : the cost of screening mammographic examinations , the cost of evaluating abnormal mammograms , and the cost of treating breast cancer ( Table 2 ) . Additional details on derivations of costs are given in the Appendix . The cost of screening mammography  was based on the average cost ( $ 91 ) reported by the National Cancer Institute 's National Survey of Mammography Facilities [ 34 ] . This cost was inflated to 1995 dollars ( $ 106 ) by using the consumer price index for medical services . We assumed that women in whom breast cancer was diagnosed continued to undergo screening mammography of the opposite breast , at the same cost , after the initial diagnosis of breast cancer . Table 2 . Information Used to Calculate Costs The cost of evaluating abnormal mammographic results was calculated as a weighted average of procedures that may follow abnormal mammograms . This cost was also inflated to 1995 dollars . The distribution and types of follow-up procedures were based on those reported by the National Cancer Institute 's National Survey of Mammography Facilities [ 35 ] . A range of costs for each procedure was based on data from Medicare , Pennsylvania Blue Cross , Group Health Cooperative , and Kaiser Permanente ( Brown M. Personal communication ) . The percentage of abnormal mammograms was based on the percentage seen with high- quality modern screening mammography ( Table 2 ) [ 36 ] . Population -based data on the cancer stage at diagnosis in screened compared with nonscreened women are sparse .
We found little evidence of effectiveness of HRLAs for promotion of exercise/improved diets .
Conclusions Overall , there is limited evidence suggesting that HRLAs are cost-effective in terms of changing health-related knowledge , behaviours or health outcomes .
The evidence that does exist indicates that HRLAs are only cost-effective when they target behaviours likely to have a large impact on overall health-related quality of life .
Background Development of new peer or lay health-related lifestyle advisor ( HRLA ) roles is one response to the need to enhance public engagement in , and improve cost-effectiveness of , health improvement interventions .
This article synthesis es evidence on the cost-effectiveness of HRLA interventions aim ed at adults in developed countries , derived from the first systematic review of the effectiveness , cost-effectiveness , equity and acceptability of different types of HRLA role .