Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale.
BACKGROUND:In both observational and randomized studies, associations with overall survival are by and large assessed on a multiplicative scale using the Cox model. However, clinicians and clinical researchers have an ardent interest in assessing absolute benefit associated with treatments. In older...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2016-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4821587?pdf=render |
| _version_ | 1818947639403610112 |
|---|---|
| author | Nicolas Girerd Muriel Rabilloud Philippe Pibarot Patrick Mathieu Pascal Roy |
| author_facet | Nicolas Girerd Muriel Rabilloud Philippe Pibarot Patrick Mathieu Pascal Roy |
| author_sort | Nicolas Girerd |
| collection | DOAJ |
| description | BACKGROUND:In both observational and randomized studies, associations with overall survival are by and large assessed on a multiplicative scale using the Cox model. However, clinicians and clinical researchers have an ardent interest in assessing absolute benefit associated with treatments. In older patients, some studies have reported lower relative treatment effect, which might translate into similar or even greater absolute treatment effect given their high baseline hazard for clinical events. METHODS:The effect of treatment and the effect modification of treatment were respectively assessed using a multiplicative and an additive hazard model in an analysis adjusted for propensity score in the context of coronary surgery. RESULTS:The multiplicative model yielded a lower relative hazard reduction with bilateral internal thoracic artery grafting in older patients (Hazard ratio for interaction/year = 1.03, 95%CI: 1.00 to 1.06, p = 0.05) whereas the additive model reported a similar absolute hazard reduction with increasing age (Delta for interaction/year = 0.10, 95%CI: -0.27 to 0.46, p = 0.61). The number needed to treat derived from the propensity score-adjusted multiplicative model was remarkably similar at the end of the follow-up in patients aged < = 60 and in patients >70. CONCLUSIONS:The present example demonstrates that a lower treatment effect in older patients on a relative scale can conversely translate into a similar treatment effect on an additive scale due to large baseline hazard differences. Importantly, absolute risk reduction, either crude or adjusted, can be calculated from multiplicative survival models. We advocate for a wider use of the absolute scale, especially using additive hazard models, to assess treatment effect and treatment effect modification. |
| first_indexed | 2024-12-20T08:34:06Z |
| format | Article |
| id | doaj.art-59600927f3d8412c8befb68746610dd9 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-20T08:34:06Z |
| publishDate | 2016-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-59600927f3d8412c8befb68746610dd92022-12-21T19:46:36ZengPublic Library of Science (PLoS)PLoS ONE1932-62032016-01-01114e015301010.1371/journal.pone.0153010Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale.Nicolas GirerdMuriel RabilloudPhilippe PibarotPatrick MathieuPascal RoyBACKGROUND:In both observational and randomized studies, associations with overall survival are by and large assessed on a multiplicative scale using the Cox model. However, clinicians and clinical researchers have an ardent interest in assessing absolute benefit associated with treatments. In older patients, some studies have reported lower relative treatment effect, which might translate into similar or even greater absolute treatment effect given their high baseline hazard for clinical events. METHODS:The effect of treatment and the effect modification of treatment were respectively assessed using a multiplicative and an additive hazard model in an analysis adjusted for propensity score in the context of coronary surgery. RESULTS:The multiplicative model yielded a lower relative hazard reduction with bilateral internal thoracic artery grafting in older patients (Hazard ratio for interaction/year = 1.03, 95%CI: 1.00 to 1.06, p = 0.05) whereas the additive model reported a similar absolute hazard reduction with increasing age (Delta for interaction/year = 0.10, 95%CI: -0.27 to 0.46, p = 0.61). The number needed to treat derived from the propensity score-adjusted multiplicative model was remarkably similar at the end of the follow-up in patients aged < = 60 and in patients >70. CONCLUSIONS:The present example demonstrates that a lower treatment effect in older patients on a relative scale can conversely translate into a similar treatment effect on an additive scale due to large baseline hazard differences. Importantly, absolute risk reduction, either crude or adjusted, can be calculated from multiplicative survival models. We advocate for a wider use of the absolute scale, especially using additive hazard models, to assess treatment effect and treatment effect modification.http://europepmc.org/articles/PMC4821587?pdf=render |
| spellingShingle | Nicolas Girerd Muriel Rabilloud Philippe Pibarot Patrick Mathieu Pascal Roy Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. PLoS ONE |
| title | Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. |
| title_full | Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. |
| title_fullStr | Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. |
| title_full_unstemmed | Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. |
| title_short | Quantification of Treatment Effect Modification on Both an Additive and Multiplicative Scale. |
| title_sort | quantification of treatment effect modification on both an additive and multiplicative scale |
| url | http://europepmc.org/articles/PMC4821587?pdf=render |
| work_keys_str_mv | AT nicolasgirerd quantificationoftreatmenteffectmodificationonbothanadditiveandmultiplicativescale AT murielrabilloud quantificationoftreatmenteffectmodificationonbothanadditiveandmultiplicativescale AT philippepibarot quantificationoftreatmenteffectmodificationonbothanadditiveandmultiplicativescale AT patrickmathieu quantificationoftreatmenteffectmodificationonbothanadditiveandmultiplicativescale AT pascalroy quantificationoftreatmenteffectmodificationonbothanadditiveandmultiplicativescale |