A validation of information provided by household respondents in health surveys

Agreement between Myocardial Infarction Patients and Their Spouses on Reporting of Data on 82 Cardiovascular Risk Exposures

BACKGROUND

The validity of exposure data collected from proxy respondents of myocardial infarction patients has scarcely been studied. We assessed the level of disagreement between myocardial infarction patients and their spouses with respect to the reporting of the patient´s cardiovascular risk exposures.

METHODS

Within the frame of the Stockholm Heart Epidemiology Program (SHEEP), a case-control study of risk factors of myocardial infarction performed in Stockholm county 1992-1994, a subset of 327 first time myocardial infarction cases aged 45-70 who survived >28 days after the event and who co-habited with a spouse or common-law spouse (proxy) were identified between 1993-04-05 and 1993-12-31. Among these, 243 cases participated along with their respective proxy in the present study. Control individuals, matched to cases by age, sex and residential area were also included (n = 243). Data were collected using questionnaires. Using conditional logistic regression we calculated for each of 82 exposures the odds ratio based on information collected from 1) myocardial infarction cases and controls [odds ratio A] and 2) proxies and the same set of controls [odds ratio B]. Disagreement was measured by calculating the ratio between odds ratio B and odds ratio A with 95% confidence intervals (CI) calculated using resampling bootstrap.

RESULTS

For the vast majority of the exposures considered including diet, smoking, education, work-related stress, and family history of CVD, there was no statistically significant disagreement between myocardial infarction patients and proxies (n = 243 pairs). However, leisure time physical inactivity (proxy bias = 1.59, 95% CI 1.05-3.57) was overestimated by spouses compared to myocardial infarction patients. A few other exposures including some sleep-related problems and work-related issues also showed disagreement.

CONCLUSIONS

Myocardial infarction patients and their spouses similarly reported data on a wide range of exposures including the majority of the traditional cardiovascular risk factors, leisure time physical inactivity being an exception.

Illness perceptions and quality of life among tuberculosis patients in Gezira, Sudan

AIMS

This study aimed to answer the following research question: What is the level of illness perceptions and quality of life among TB patients in Gezira state?.

METHODS

A descriptive study design was used. Newly diagnosed smear positive TB patients registered in Gezira state in 2010 (n=425) formed the study population. The illness perceptions were measured by using Brief Illness Perceptions Questionnaire (BIPQ). Health Related Quality of Life (HRQoL) was assessed by means of the 12-item short form Health Survey questionnaire (FS-12).

RESULTS

TB patients saw TB as having minor consequences, TB not being very well controlled by treatment, and TB as lasting long as a disease; they also associated several symptoms with TB. Furthermore, the patients had relatively poor physical and mental quality of life. Identity, consequences, personal control and emotional representations were associated with poor physical quality of life while concern about illness was associated with poor mental quality of life.

CONCLUSION

The illness perceptions of the TB patients might influence their adherence to treatment. The poor quality of life of the TB patients in the different areas of quality of life such as daily activities and work, calls for programmes to strengthen TB information, education and counselling.

Accuracy of proband reported family history: the NHLBI Family Heart Study (FHS)

Proband-reported family histories are widely used in research and counseling, yet little is known about the validity of family history reporting. The Family Heart Study (FHS), a population-based study of familial cardiovascular disease, gathered family history information from 3,020 middle-aged probands in four U.S. communities. Probands reported on the history of coronary heart disease (CHD), diabetes, hypertension, and asthma among a total of 10,316 living relatives (9,186 siblings, 1,130 parents) and 2,685 spouses. Questionnaires were returned by 6,672 siblings, 901 parents, and 2,347 spouses, yielding response rates of 73, 79, and 87%, respectively. Utilizing the relatives' self-report as the standard, sensitivity of the proband report on their spouse, parent, and sibling was 87, 85, and 81% for CHD, 83, 87, and 72% for diabetes, 77, 76, and 56% for hypertension, and 66, 53, and 39% for asthma, respectively. Most specificity values were above 90%. Analyses using generalized estimating equations (GEE) were performed to evaluate differences in proband accuracy based on the proband's age, gender, disease state, center, and ethnicity. In multivariate models, age, gender, and disease status were significantly associated with the accuracy of proband's report of sibling disease history, but had little effect on the accuracy of their report on spouses or parents. In general, older probands were significantly less accurate reporters of disease than younger probands. These results demonstrate that CHD family history can be captured effectively based on proband reports, but suggest that additional family contacts may be helpful when working with older probands or with chronic diseases that have few recognized medical events or procedures.

Inflation of sibling recurrence-risk ratio, due to ascertainment bias and/or overreporting

One widely used measure of familial aggregation is the sibling recurrence-risk ratio, which is defined as the ratio of risk of disease manifestation, given that one's sibling is affected, as compared with the disease prevalence in the general population. Known as lambdaS, it has been used extensively in the mapping of complex diseases. In this paper, I show that, for a fictitious disease that is strictly nongenetic and nonenvironmental, lambdaS can be dramatically inflated because of misunderstanding of the original definition of lambdaS, ascertainment bias, and overreporting. Therefore, for a disease of entirely environmental origin, the lambdaS inflation due to ascertainment bias and/or overreporting is expected to be more prominent if the risk factor also is familially aggregated. This suggests that, like segregation analysis, the estimation of lambdaS also is prone to ascertainment bias and should be performed with great care. This is particularly important if one uses lambdaS for exclusion mapping, for discrimination between different genetic models, and for association studies, since these practices hinge tightly on an accurate estimation of lambdaS.

Knowledge of medical history information among proxy respondents for deceased study subjects

Proxy respondents were interviewed for 96 decedents in an occupational cohort. A second respondent was interviewed for 59 decedents. Medical records were reviewed to validate questionnaire information. The percentage of respondents who answered "don't know" (non-response) to questions about medical condition ranged from 5% (cancer and heart disease) to 17% (ulcers). Non-response rates were lowest among spouses, intermediate among children, parents, and siblings, and highest among other relatives and friends. Among 41-55 pairs, depending on the condition, agreement between paired respondents was excellent (kappa > 0.75) for ulcers, cancer, diabetes, and lung disease. A higher percentage of medical records was obtained for decedents with spouse respondents and for decedents with more recent dates of death. Sixty percent or more of the medical records were obtained for patients with cancer (n = 30), heart disease (n = 26), stroke (n = 9), and liver disease (n = 10). The positive predictive value of the proxy respondent information for these conditions was 93, 81, 78, and 60%, respectively.

[A comparison of the information obtained in a health survey by interview with primary care registries]

To estimate the levels of underreporting of medical visits and to compare the reporting of chronic restrictive diseases, 203 individuals who had been visited in a Primary Health Center were interviewed in the period of two weeks following the medical visit. Underreporting of a medical visit was identified in 31 (15.3%) of the users. The level of underreporting was not related with age, sex, education or socioeconomic status. Reporting of chronic restrictive illness was compared with the information recorded in the user's medical record. The highest global agreement (91.6%) was observed for hypertensive disease (kappa index = 0.71), while the lowest agreement was found for chronic back pain (global agreement = 77.8% and kappa index = 0.14). Since underreporting of medical visits was moderate, the results suggest that this question can be used for the analysis of social differences in the access to health services. Nevertheless, estimation of the prevalence of chronic limiting conditions in a health interview survey should be done with great caution.

Direct methods of obtaining information on cigarette smoking in occupational studies

Many occupational epidemiology studies require complete and accurate information on tobacco use to control for confounding by smoking and to assess interactions of smoking with workplace exposures. This paper reviews and evaluates the availability, reliability, validity, and efficiency of the various data sources and techniques for obtaining individual smoking data, including existing records, biological markers, and surveys. Emphasis is placed on the highly problematic issue of obtaining retrospective smoking histories. In general, the survey technique is currently deemed the most feasible approach for obtaining lifetime smoking histories. Both theoretical and practical aspects of smoking surveys are discussed in detail and are illustrated with a review of the recent literature and with data from two recent retrospective cohort studies conducted at the University of Pittsburgh. Several recommendations involving both the use of smoking data and areas for future methodologic research are presented. These include (1) justification for collecting smoking data in occupational studies based primarily on the potential for smoking to act as an effect modifier rather than solely as a confounder, (2) checks for reliability and validity in all studies which involve the collection of smoking data, (3) more methodologic research to better understand the impact that missing, unreliable, and invalid smoking data may have on the ability to detect and quantify important smoking-exposure interactions, and (4) an assessment of the correlation between biological markers and cigarette carcinogen exposure.

The use of surrogate respondents to obtain questionnaire data in case-control studies of neurologic diseases

In 1984-85, the authors assessed the reliability of surrogate respondents to provide interview data for the specific items of a case-control study of Alzheimer's disease conducted in Italy. For all questions of the interview, responses of 52 non-demented subjects were compared to responses of their next-of-kin. In 21-27% of the pairs the next-of-kin was unable to answer questions about general anesthesia, antacid drug use, and age of mother and father at index birth. However, the surrogate respondent was able to answer 45 of 57 tested items with agreement greater than 80%. Questions about use of hard liquor and behavior pattern yielded agreement of 71-75%, while those about number of jobs, and number of cigarettes per day yielded 62-63% agreement. For those who provided information about antacid drug use, agreement was poor. These findings are encouraging for the use of next-of-kin respondents in case-control studies of Alzheimer's disease or other neurologic conditions for which the subject cannot provide historical information.

A comparison of mail, telephone, and home interview strategies for household health surveys

The method of data collection in household health surveys can be a major determinant of cost and data quality. A survey strategy can comprise mail, telephone, or home interview methods, individually or in combination to follow up non-respondents. The purpose of this study in Montreal was to compare cost and data quality of various strategies. Strategies which began with mail or telephone contact, followed by the two other methods, provided response rates as high as a home interview strategy (all between 80 and 90 per cent), for one-half the cost of home interviews when used as the sole method. The telephone response rate was higher than the mail response rate. Comparing different follow-up approaches to strategies beginning with mail or telephone, it proved less costly, and equally effective, to use home interviewing as a last resort for persistent non-respondents. Validity of response (comparing individual responses with records of a government health insurance data bank) and willingness to answer sensitive questions were greatest in mail strategy.