TITLE: Community-based cross-sectional survey
AUTHORS: Kajiru Gad Kilonzo, Stefanie J. Krauth, Jo Halliday, Clive Kelly, Stefan Siebert, Gloria Temu, Christopher Bunn, Nateiya M Yongolo, Sally Wyke, Emma McIntosh, Blandina Mmbaga

[DESCRIPTION]
This protocol details community-based cross-sectional survey.

[GUIDELINES]
A community-based cross-sectional survey will be used to estimate the prevalence, economic and societal impact of arthritis in the community setting using clinical screening tools, economic and quality of life questionnaires. The community survey will comprise a representative sample of all residents (aged over 5 years old) living in Tanzania’s Hai district in the Kilimanjaro region, and one street in the Moshi urban setting.

[STEPS]
SECTION: Participant selection
1. Based on sample-size calculations, the study will recruit 1050 households (approximately 5701 individuals) for this cross-sectional survey, to achieve a confidence level of 95% and assuming a 15% prevalence of MSK (as estimated in the pilot study).
SECTION: Participant selection
2. Two-stage cluster sampling with replacement and probability proportional to the size of the village population will be used. (25)
SECTION: Participant selection
3. In the first stage villages will be selected from a sampling frame, and one village can be selected more than one time with the probability of selection proportional to the size of the village. In the second stage, households will be selected with random probability.
SECTION: Participant selection
4. The selection of households in the second stage benefits from the existing organisation of Tanzania households within Balozi, as the Balozi ‘informal’ infrastructure will be used to enumerate the households and to inform the households in the villages about the aims of the survey.
SECTION: Participant selection
5. In addition, in the Moshi urban setting one street is selected using convenience sampling. All eligible members of selected households identified in the community setting will be invited to participate in the study and asked to provide written informed consent as described in the consent section below.
SECTION: Data collection
6. A three-stage screening process for all participants will be followed (See Table 1: Summary of community-based research).

Table 1: Summary of community-based research 
      Community survey:     Setting  Randomly selected villages in HAI district & Majengo community in   Moshi urban     Participants  Members of selected households (general population)     Research methods  Questionnaire surveys      Physical examinations       Medical imaging & blood testing    Instruments:  Tier 1: General (all participants):    (tiered according to GALS results)  GALS (Swahili version)    *denotes instruments applied to   participants below 18 years of age  pGALS (Swahili version)*       WHO DAS (Swahili version)       EQ5D (Swahili version)       Demographic questionnaire       Short health questionnaire       Short health economics questionnaire       CHU 9D (Swahili version)*      Tier 2: GALS+ participants:      HAQ (Swahili version)       Global Health + modified Joint Pain Visual Analog scale (Swahili   version)       REMS       pREMS*       66/68 swollen/tender joint count*      Tier 3: REMS+/pREMS+ participants:      Blood testing       Ultrasound       Long health economic questionnaire      Additional health questions       Further medical examinations (height, weight, blood pressure, details on   identified MSK disorders)       The Tier 2 and 3 tools (excluding medical imaging, bloods and further   medical exams) will also be administered the GALS- control sample from Tier1   who are age and sex-matched to REMS+/66/68 joint count+ participants in Tier3    Community-based   qualitative research    Setting:  Randomly selected villages in HAI district    Participants:  Members of selected households (general population)    Research methods:  Focus groups (GALS+ community members) (Appendix 18)      Semi structured interviews (GALS+ community members)      Visualisation methods      Co-creation methods  
 
SECTION: Data collection
7. In the first stage, all participants will be assessed using a version of the Gait Arms Legs Spine (GALS) screening test adapted for the local context and translated for delivery in Swahili. (26)
SECTION: Data collection
8. An adapted version of the paediatric version (pGALS) will be delivered in Swahili for those aged 5-17 years (27) who declare locomotor limitations or symptoms. The pGALS has previously been translated into Swahili, among other languages, and shown to be practical and acceptable in children in Malawi. (28)
SECTION: Data collection
9. In addition, All participants will be administered a demographic questionnaire, a short health questionnaire, and a short health-economics questionnaire (only participants >11 years).
SECTION: Data collection
10. Furthermore, adult participants (18+ years) will be administered the WHO Disability Assessment Questionnaire (WHO DAS), and the EQ-5D questionnaire (29,30), whereas minors under 18 will be administered the CHU 9D questionnaire (31).
SECTION: Data collection
11. Individuals who test negative in the GALS examination will be assessed whether they are of the same sex and similar age range as already-identified REMS+ participants and, if so, will be included as controls.
SECTION: Data collection
12. GALS- individuals who are not included as controls during their first visit will be asked for assent to be re-visited in case of further questions and will be revisited in case they are an appropriate control for a REMS+ case.
SECTION: Data collection
13. The second stage will be applied to GALS+ individuals as well as sex and age matched controls for REMS+ individuals and will include the modified Health Assessment Questionnaire (HAQ), and the Global Health questionnaire.
SECTION: Data collection
14. GALS+ individuals (but not controls) will be administered REMS and the 66/68 swollen/tender joint count + Joint Pain Visual Analog Scale (VAS).
SECTION: Data collection
15. In the third stage, all REMS+ individuals and controls will be administered the long health-economic questionnaire (only participants >11 years), be asked additional questions about their health including the presence of additional non-communicable diseases, and have their height, weight and blood pressure measured.
SECTION: Data collection
16. REMS+ individuals (but not controls) will have their blood taken for laboratory analysis. In addition, ultrasound imaging will be taken from all affected joints (see Laboratory and radiological data collection section) and additional details about the participants’ MSK disorders will be recorded.