Patients' preferences for a prostate cancer consultation, a discrete choice experiment

Four basic medical decision making models are commonly discussed in the literature in reference to physician-patient interactions. All fall short in their attempt to capture the nuances of physician-patient interactions, and none satisfactorily address patients' preferences for communication and other attributes of care. Prostate cancer consultations are one setting where preferences matter and are likely to vary among patients. Fortunately, discrete choice experiments are capable of casting light on patients' preferences for communication and other attributes of value that make up a consultation before the consultation occurs, which is crucial if patients are to derive the most utility from the process of reaching a decision as well as the decision itself. The results of my dissertation provide strong support to the notion that patients, at least in the hypothetical setting of a DCE, have identifiable preferences for the attributes of a prostate cancer consultation and that those preferences are capable of being elicited before a consultation takes place. Further, patients' willingness-to-pay for the non-cost attributes of the consultation is surprisingly robust to a variety of individual level variables of interest. ^

A systematic review of literature to compare the fertility desires among HIV positive women and cancer survivors

Background. Decision-making on reproductive issues is influenced by an interplay of individual, familial, medical, religious and socio-cultural factors. Women with chronic medical illnesses such an HIV infection and cancers are often fraught with decisional conflicts about child-bearing. With increase in the incidence of these illnesses as well as improvement in survival rates, there is a need to pay due attention to the issue of reproductive decision-making. Examining the prevalence and determinants of fertility desires in the two groups in a comparative manner would help bring to light perception of the medical community and the society in general on the two illnesses and the issue of motherhood. ^ Methods. Systematic literature search was undertaken using databases such as MEDLINE (PubMED), MEDLINE (Ovid), PsycInfo and Web of Science. Articles published in English and English language abstracts for foreign articles were included. Studies that explore ‘fertility desires’ as the outcome variable were included. Quantitative studies which have assessed the prevalence of fertility desires as well as qualitative studies which have provided a descriptive understanding of factors governing reproductive desires were included in the review. ^ Results. A total of 34 articles (29 studies examining HIV and 5 studies examining cancer in relation to fertility desires). Variables such as age, stage of illness, support of spouse and family, perception of the medical community and one’s own view of motherhood were key determinants among both groups. ^ Conclusion. There is a need for uniform, systematic research in this field. It is important that health care workers acknowledge these decisional conflicts, include them as part of the medical care of these patients and provide guidance with the right balance of information, practicality and compassion.^

Effects of informative censoring on the hazard function: Application to the proportional hazards regression model

The standard analyses of survival data involve the assumption that survival and censoring are independent. When censoring and survival are related, the phenomenon is known as informative censoring. This paper examines the effects of an informative censoring assumption on the hazard function and the estimated hazard ratio provided by the Cox model.^ The limiting factor in all analyses of informative censoring is the problem of non-identifiability. Non-identifiability implies that it is impossible to distinguish a situation in which censoring and death are independent from one in which there is dependence. However, it is possible that informative censoring occurs. Examination of the literature indicates how others have approached the problem and covers the relevant theoretical background.^ Three models are examined in detail. The first model uses conditionally independent marginal hazards to obtain the unconditional survival function and hazards. The second model is based on the Gumbel Type A method for combining independent marginal distributions into bivariate distributions using a dependency parameter. Finally, a formulation based on a compartmental model is presented and its results described. For the latter two approaches, the resulting hazard is used in the Cox model in a simulation study.^ The unconditional survival distribution formed from the first model involves dependency, but the crude hazard resulting from this unconditional distribution is identical to the marginal hazard, and inferences based on the hazard are valid. The hazard ratios formed from two distributions following the Gumbel Type A model are biased by a factor dependent on the amount of censoring in the two populations and the strength of the dependency of death and censoring in the two populations. The Cox model estimates this biased hazard ratio. In general, the hazard resulting from the compartmental model is not constant, even if the individual marginal hazards are constant, unless censoring is non-informative. The hazard ratio tends to a specific limit.^ Methods of evaluating situations in which informative censoring is present are described, and the relative utility of the three models examined is discussed. ^