Frequently repeated measurements -our experience of collecting data with SMS.

BACKGROUND: As technology is advancing, so are the possibilities for new data collection methods in research, potentially improving data quality and validity of the results. In Sweden, a system using frequent repeated data collection using text messages, SMS Track, has been used in clinical research for more than a decade. In this paper, compliance with repeated text message questions was examined across five different studies, i.e. if compliance was 1: associated with study-specific factors (age or gender of the subjects, the condition, its' severity or course, i.e. improvement, relapse or steady state) and/or. 2: associated with the methodology itself (the question being asked, the frequency and number of questions, duration of data collection, initial compliance or the management of the system). METHODS: Descriptive comparisons were done across five studies. Three studies were collecting weekly responses over at least 52 weeks ("Weekly studies") and were used to investigate the effect of age, sex and pain severity on compliance, the effect of early compliance for late compliance, and finally the early occurrence of two successive weeks with non-compliance. RESULT: Compliance was excellent across all five studies, and only influenced somewhat by age, sex and pain-level. The factor "study" remained significant in the final model thus the observed differences may be a result of the conditions studied but does not seem to be attributable to severity or development of these conditions. Number and frequency of questions did not influence compliance, nor did study duration. CONCLUSIONS: Compliance was excellent in the included studies and was not affected by population factors. However, differences in compliance were observed that cannot be easily explained and warrant further investigation. In particular, the nature of the variables or the management of the study are potential areas for further investigations.

Validity and test-retest reliability of an at-work production loss instrument.

BACKGROUND: Besides causing ill health, a poor work environment may contribute to production loss. Production loss assessment instruments emphasize health-related consequences but there is no instrument to measure reduced work performance related to the work environment. AIMS: To examine convergent validity and test-retest reliability of health-related production loss (HRPL) and work environment-related production loss (WRPL) against a valid comparable instrument, the Health and Work Performance Questionnaire (HPQ). METHODS: Cross-sectional study of employees, not on sick leave, who were asked to self-rate their work performance and production losses. Using the Pearson correlation and Bland and Altman's Test of Agreement, convergent validity was examined. Subgroup analyses were performed for employees recording problem-specific reduced work performance. Consistency of pairs of HRPL and WRPL for samples responding to both assessments was expressed using Intraclass Correlation Coefficient (ICC) and tests of repeatability. RESULTS: A total of 88 employees participated and 44 responded to both assessments. Test of agreement between measurements estimates a mean difference of 0.34 for HRPL and -0.03 for WRPL compared with work performance. This indicates that the production loss questions are valid and moderately associated with work performance for the total sample and subgroups. ICC for paired HRPL assessments was 0.90 and 0.91 for WRPL, i.e. the test-retest reliability was good and suggests stability in the instrument. CONCLUSIONS: HRPL and WRPL can be used to measure production loss due to health-related and work environment-related problems. These results may have implications for advancing methods of assessing production loss, which represents an important cost to employers.

The types and frequencies of improved nonmusculoskeletal symptoms reported after chiropractic spinal manipulative therapy.

OBJECTIVE: To investigate the frequency and types of improved nonmusculoskeletal symptoms reported after chiropractic spinal manipulative therapy. DESIGN: Retrospective information obtained by chiropractors through standardized interview of patients on return visit within 2 weeks of previous treatment. SETTING: The private practice of 87 Swedish chiropractors (response rate 81%). SUBJECTS: Twenty consecutive (presumably naive) patients per chiropractor (1504 valid questionnaires returned, 86% of optimal number of replies). INTERVENTION: Spinal manipulation with or without additional therapy provided by chiropractors. MAIN OUTCOME MEASURES: Self-reported improved nonmusculoskeletal symptoms (reactions). RESULTS: At least I reaction was reported after the previous treatment in 21% to 25% of cases. Of these responses, 26% were related to the airway passages (usually reported as "easier to breathe"), 25% were related to the digestive system (mostly reported as "improved function"), 14% were classified under eyes/vision (usually reported as "improved vision"), and 14% under heart/ circulation (about half of these reported as "improved circulation"). The number of spinal areas treated was positively associated with the number of reactions. CONCLUSION: A minority of chiropractic patients report having positive nonmusculoskeletal reactions after spinal manipulative therapy but such reports cluster predominantly around specific symptoms. It would be interesting to find out if these can be verified objectively and, if so, to investigate if they are caused by the treatment or if they are signs of natural variations in human physiology.