CKD Understanding risk factors for progressive chronic kidney disease in Malawi to inform interventions for earlier detection and prevention (Impso Study)
Malawi
Identification
DDI-MWI-MEIRU-CKDK-2024-v1
CKD Understanding risk factors for progressive chronic kidney disease in Malawi to inform interventions for earlier detection and prevention (Impso Study)
[Chichewa]: Kumvetsetsa ziopsezo zomwe zimayambitsa matenda a impso omwe akupita kutsogolo ku Malawi kuti adziwitse njira zothandizira kuti azindikiridwe ndi kupewedwa mwamsanga (Impso study)
| Name | Country code |
|---|---|
| Malawi | MWI |
Sample Survey
Background
The global burden of chronic kidney disease (CKD) is rising, disproportionately impacting on low- and middle-income countries. In African populations, use of serum creatinine to estimate glomerular filtration rate (GFR) significantly underestimates CKD prevalence, contributing to its under-recognition as a health problem. Serum cystatin C provides more accurate estimates of Iohexol measured GFR than creatinine. Early diagnosis and treatment of CKD, targeted towards high-risk individuals, is essential to reduce premature morbidity and mortality. However, little is known about risk factors for CKD development and progression in Africa owing to limited longitudinal data. This study aims to determine risk factors for progressive kidney function decline among adults living in rural, northern Malawi.
Methods
The Impso study is an ongoing prospective study being conducted in a general population cohort in rural Karonga, Malawi. We are recruiting adults aged 18 years and over who participated in two previous population-based surveys of long-term health conditions, over five years apart. New household-level data is being collected on CKD risk factors, alongside blood and urine samples. Cystatin C and creatinine will be tested on individual-level paired, stored serum samples collected at three longitudinal time points. Urine will undergo dipstick urinalysis, microscopy and testing for albumin and creatinine to quantify proteinuria. The primary outcome will be sustained 25% reduction in estimated GFR (eGFR) from baseline and change in eGFR category, determined using serum cystatin C. Multivariable logistic regression will be used to determine effect size estimates of key risk factors for kidney function decline.
Discussion
This study will provide important data on risk factors for eGFR decline and CKD progression amongst Malawian adults. The findings will inform future research into important context-specific risk factors, and could directly inform future health policies in Malawi for targeting CKD screening, prevention and treatment strategies to the highest risk patient groups.
Sample survey data [ssd]
Individual
Version
This version provides metadata for raw datasets as they appear in our databases.
2025-06-06
Scope
| Topic | Vocabulary |
|---|---|
| HEALTH | Specific diseases, disorders and medical conditions |
| HEALTH | Public Health |
| LONGITUDINAL | Longitudinal: Cohort/Event-based |
| INTERVIEW | Face-to-face interview: Computer-assisted (CAPI/CAMI) |
| MEASUREMENTS AND TESTS | Physical measurements and tests |
Coverage
Chilumba, Karonga
This study is recruiting adults living within the Karonga Health and Demographic Surveillance Site (HDSS), who meet the following eligibility criteria
• Alive, self-defined as resident within the Karonga HDSS , and provided consent to ongoing participation in the HDSS and sampling for further studies.
• Participated in both the NCD (2013-16) and HLM-LTC (2021-25) population surveys.
• Aged >= 18 years at the time of participation in the NCD (2013-16) survey.
• Availability of baseline cystatin C tested on a stored historical serum sample.
• Baseline eGFR (estimated using cystatin C, eGFRcysc) <90 ml/min/1.73m2.
Exclusion criteria include:
• Unable to provide informed written consent, or assent with proxy informed written consent from a nominated guardian.
• Acute presentation of physical or mental illness or rapidly declining poor health at the time of attempted recruitment, which might be exacerbated by participation in the study.
• Currently a hospital inpatient at time of follow-up (at time of screening for participation in Impso study)
• Pregnant at the time of baseline sample collection for cystatin C testing, and/or when approached for recruitment into the current study, with pregnancy to continue beyond the end of the study recruitment period.
Producers and sponsors
| Name | Affiliation |
|---|---|
| Charlotte Snead | Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA , UK |
| Name | Affiliation | Role |
|---|---|---|
| Alison Price | LSHTM | PhD Supervisor |
| Felix Limbani | MLW, LSTM | PhD Supervisor |
| Dominic Taylor | North Bristol NHS Trust, UK | PhD Supervisor |
| Henry Mwandumba | MLW, LSTM | Primary PhD Supervisor |
| Amelia Crampin | MEIRU, LSHTM, University of Glasgow | PhD Collaborator |
| Chimota Phiri | Kamuzu University of Health Sciences | PhD Collaborator |
| June Fabian | University of the Witwatersrand | PhD Collaborator |
| Robert Kalyesubula | Makerere University | PhD Collaborator |
| Estelle Mclean | Formerly LSHTM | PhD Collaborator |
| Name | Role |
|---|---|
| Wellcome Trust | Wellcome Trust Clinical PhD Fellowship funded CS for this work (including the primary data collection) |
| Wellcome Trust | This work uses linked data from the NCD survey, which was funded by these grants |
| Wellcome Trust | This work uses linked data from the HLM-LTC survey, which was funded by this grant |
| GSK Africa Non-Communicable Disease Open Lab | This work uses linked data from the ARK study, which was funded by this grant |
| Wellcome Trust | This work uses cystatin c and creatinine data tested on stored serum samples as part of a separate study, funded awarded to Professor Segun Fatumo through this grant |
| UKRI/MRC | This work uses cystatin c and creatinine data tested on stored serum samples as part of a separate study, funded awarded to Professor Segun Fatumo through this grant |
Sampling
The sample is a convenience sample identified by screening the MEIRU databases for all potential individuals meeting the eligibility (inclusion) criteria, based on availability of linked historic data including stored serum samples already tested for creatinine and cystatin C in previous linked studies. Potentially eligible individuals are approached at their household to invite participation in the study, a minimum of three months after their participation in the HLM-LTC survey. Up to three attempts are made to visit each potentially eligible participant, including at different times of day, to facilitate recruitment of adults of working age who may be less likely to be at home and thereby minimise selection bias. Once approached, potential participants are screened for exclusion criteria prior to recruitment.
The target sample size is 1000 participants. A sample of n=1000 participants with eGFRcysc available at baseline will give >=80% power to detect odds ratio (OR) of between 1.66 and 4.38 for the effect of risk factors on eGFR decline. This is assuming that; (1) the risk factors of interest increase probability and rate of eGFR decline; (2) risk factor prevalences range between 5% and 30%; and (3) eGFR decline outcome measures occur in 5 to 15% of individuals unexposed to the risk factors of interest.
No deviations from sample design to date (04.08.25) - study ongoing.
The study is still ongoing, due to complete later in 2025. Up to and including 03/08/25, cooperation with the study by individuals approached to take part has been very positive. Of 947 individuals who we have attempted to approach, 915 were found. 32 were not found (10 had died, 13 had moved out of the HDSS, 9 could not be found at their household despite three attempts). Of the remaining 915, 898 have been recruited (98%). Three were not eligible, and 14 (1.5%) declined participation.
Survey instrument
The following ODK forms are used in this study. The languages used are as follows: English, Chichewa and Tumbuka.
Informed Consent form
-Collecting consent data
CKD_SF36_QESTIONNAIRE_V01(RAND 36-Item Short Form Survey Instrument )
- Health-related quality of life (HrQOL)
CKD_SCREENING_TOOL_V01
- Screening questions to determine optimal timing for early morning biological sample collection
CKD_URINE_COLLECTION_V01
-Collecting data related to mid-stream urine (MSU) sample collection and household level dipstick urinalysis test results using a standardised information sheet
CKD_RISK_FACTORS_V03
- Covering; risk factors for CKD, including detailed questions on medical history, symptoms and medication use, supported by review of the participant's health passport if available
CKD_EQ5D-5L_V01
- EQ-5D-5L translations approved by EuroQol
CKD_HIV_Form_V02
- Collecting HIV testing data
Data collection
Initial data (consent data, CKD risk factors, screening questions, HIV testing for selected participants, SF36 HrQOL and EQ5D HrQOL) is collected at an initial baseline household visit. A single serum sample and a baseline (1st) mid-stream urine sample is collected in the early morning either on the day imemdiately after recruitment, or as soon as possible thereafter. This marks the completion of baseline data collection. Follow-up data collection (follow-up/2nd mid-stream urine sample) takes place only for selected participants with abnormalities on the baseline urine sample (dipstick abnormalities or organisms seen on gram stain) Further follow-up data collection (2nd follow-up/3rd mid-stream urine sample) takes place only for selected participants with new microscopic hamaturia present on the follow-up (2nd) urine sample, which was not present on the 1st (baseline) urine sample.
- Face-to-face [f2f]
| Name | Affiliation | Abbreviation |
|---|---|---|
| Malawi Epidemiology and Intervention Research Unit | Agency | MEIRU |
Spot checks are undertaken of data collection (field checks to observe data collection processes, particularly during the first 12 months of the study, and review of photographs of urine dipsticks)
Meetings are held between the study lead and field team (either in person or via phone call) a minimum of two to three times per week.
Regular meetings are held between the study lead and the PhD supervisors (co-investigators).
Weekly data checks are run to resolve any data issues and interrogate/resolve any missing data as soon as possible.
Spot checks are undertaken of data collection (field checks to observe data collection processes, particularly during the first 12 months of the study, and review of photographs of urine dipsticks)
Baseline data collection at the initial household visit, including information giving and consent process, takes about 1.5 to 2 hours per participant.
Up to and including 03/08/25, cooperation with the study by individuals approached to take part has been very positive. Of 947 individuals who we have attempted to approach, 915 were found. 32 were not found (10 had died, 13 had moved out of the HDSS, 9 could not be found at their household despite three attempts). Of the remaining 915, 898 have been recruited (98%). Three were not eligible, and 14 (1.5%) declined participation.
All field staff underwent training in GCP and in the specific study SOP prior to initiation of any data collection. Study SOP training included training and practice sessions covering study information giving, informed consent, chronic kidney disease as a health condition, study processes, data collection tools, sample collection (both theory and practical training), data management and clinical referral processes. Training also covered linked MEIRU work (HLM-LTC survey and overview of the HDSS).
External pilot data was collected from 27 community participants between 14/02/24 and 01/03/24, with informed, written consent obtained from all pilot participants.
On average, the baseline data collection visit (information giving, informed consent, ODK questionnaires, delivery of urine collection instructions, and CKD counselling advice) takes between 1.5 and 2 hours per participant. Sample collection visits take between 20 and 30 minutes per participant.
Interviews are conducted in the langauge of the participant's choice with all study infromation, materials and questionnaires available in Chitumbuka, Chichewa and English.
No specific events have taken place to affect data quality, though the total duration of data collection has been longer than anticipated due to loss of staff, re-recruitment and re-training.
Weekly data checks are run with data reviewed by the study lead and by the MEIRU data team. Meetings are held between the study lead and field team (either in person or via phone call) a minimum of two to three times per week ensuring that any field issues are resolved as soon as posible. The study lead also participants in fortnightly meetings that take place with the wider MEIRU field teams across all studies being conducted in the Karonga HDSS, for cross-study discussion and resolution of any general field issues and to share updates on study progress.
Data processing
First level Data checks were programmed within the ODK software and inconsistent records are highlighted and corrected right away in the field. We are also implementing a double entry system for paper based questionnaires and inconsistencies are highlighted and corrected in consultation with the field teams. There are also access based and STATA based programs that have been written to facilitate cleaning of the data and making it ready for analysis.
Access policy
Chilumba
Data Access
| Name | Affiliation | URL | |
|---|---|---|---|
| Malawi Epidemiology and Intervention Research Unit | Agency | https://www.meiru.info | data@meiru.mw |
These data are made available for licensed access under the following conditions:
- Data and other material provided by MEIRU will not be redistributed or sold to other individuals, institutions or
organisations without MEIRU's written agreement. - In the case of multi-centre datasets, data originating from a single contributing member centre of the collaboration may not
be analysed or reported on in isolation without the express permission of the member centre concerned. - No attempt will be made to re-identify respondents, and there will be no use of the identity of any person or establishment
discovered inadvertently. Any such discovery will be reported immediately to MEIRU. - No attempt will be made to produce links between datasets provided by MEIRU or between MEIRU data and other
datasets that could identify individuals. - Any books, articles, conference papers, theses, dissertations, reports or other publications employing data obtained from
MEIRU will cite the source, in line with the citation requirement provided with the dataset. - An electronic copy of all publications based on the requested data will be sent to MEIRU.
- MEIRU, MEIRU research collaborators and the relevant funding agencies bear no responsibility for the data's use or
interpretation or inferences based upon it.
Metadata production
DDI-MWI-MEIRU-CKDK-2024-v1
| Name | Abbreviation | Affiliation | Role |
|---|---|---|---|
| Malawi Epidemiology and Intervention Research Unit | MEIRU | Agency | |
| Paul Kambiya | PK | MEIRU | Planning |
| Dominic Nzundah | DN | MEIRU | Metadata review and supervision |
| James Unique Kambiri | JUK | MEIRU | Metadata entry and editing |
| Themba Chirwa | TC | MEIRU | Review |
2024-07-10
Metadata version
1.0