The number of patients with critical illness has not been accurately quantified, although data suggests that it exceeds 10% for hospital inpatients, and the in-hospital mortality of critically ill patients is between 18-82%. In Africa, the prevalence of critical illness is likely to be higher due to a greater burden of disease, and the associated mortality higher due to limited resources.

This is a prospective, observational study to rapidly establish the prevalence of critical illness in in-hospital adult patients in Africa, and the resources available to provide essential critical care (care that should be available to every patient in the world) and factors associated with mortality.

Rapid dissemination of these findings may help mitigate mortality from critical illness in Africa. These points provide the rationale for the African Critical Illness Outcomes Study (ACIOS).

Study Objective

The objectives of this study are to determine: 1. The proportion of hospital patients who are critically ill, 2. The mortality associated with critical illness, 3. The proportion of critically ill patients who receive essential emergency and critical care, 4. The relationship between essential emergency and critical care provision, and mortality, and 5. The availability of resources necessary to provide essential emergency and critical care.

Study Design

An African multi-centre prospective observational cohort study of adult (≥18 years) in-hospital patients. Patient follow up will be for a maximum of 7 days in-hospital.

The primary outcome is in-hospital mortality in adult hospital patients with and without critical illness in Africa.

The intention is to provide a representative sample of the mortality, the risk factors associated with mortality in adult patients with critical illness, and the resources available and interventions provided to treat critical illness in Africa. This study will run between September and November 2023.

Prepatory Work

This study will be run by the African Perioperative Research Group (APORG), with a network of over 600 hospitals in more than 40 African countries which has successfully conducted the African Surgical Outcomes Study (ASOS), the ASOS-2 Trial, the African COVID-19 Critical Care Outcomes Study (ACCCOS) and the African Paediatric Surgical Outcomes Study (ASOS-Paeds).

Importance of this Study

To decrease the mortality associated with critical illness in Africa, it is important to rapidly establish the potential risk factors for mortality, and resources available to manage these patients. The APORG network has the capacity to provide these data timeously.

Study Dates

National lead will determine (with their team) the start date for their country

Declare your interest

Please click on the link below to declare your interest for the ACIOS study.

Declare your interest


To download the FAQ document, please click here
To download the manual of ‘Standard Operating Procedures (SOPs)’, please click here

Administrative Questions

Where can I find all the up to date study documents?

All study documents are available on the ACIOS Website ( and on the APON platform

How can I confirm my registration as a National Leader, Hospital Leader, or Hospital Investigator?

If you are unsure whether you have registered for the study, please email us at This email address is being protected from spambots. You need JavaScript enabled to view it. and we will confirm whether or not you have completed the online registration.

There is a concern about the feasibility of the study as all admitted patients are potential candidates for the study (if they fulfil the inclusion criteria).

We have adopted the following principles to ensure the feasibility of the study: The African Perioperative Research Group (APORG) has extensive continental study experience in large collaborative studies e.g. the African Surgical Outcomes Study (ASOS), ASOS-2, the African Critical Care Covid-19 Outcomes Study (ACCCOS) and the African Paediatric Outcomes Study (ASOS-Paeds). The learning from this group has been incorporated into this study. This includes:
  • 1. A single day of data collection, and

  • 2. An outcome limited to in-hospital mortality, censored at 7 days.

  • 3. A limited dataset.

    The hospital lead investigators can expand their study team during the data collection period if necessary. We have a suggested standard operating procedure (SOP) for how hospitals may develop local ward-based investigator teams to facilitate data collection. Importantly, all local investigators will be listed in the publication as collaborators, and will be PubMed listed. We also encourage investigators to seek additional funding to support their facility-level data collection. Based on these points, we consider this study to be feasible.

    What is APON and why do I need to register on this platform?

    APON is a digital platform designed for researchers in Africa to connect, share and collaborate on various research projects across the continent. Only investigators who have registered can be included in the publication(s) for ASOS-Paeds and so it is important that all hospital investigators who take part register on APON. To register, go to:

    Waiver of consent

    We request a waiver of consent for the following reasons:
  • 1. This study is in essence a large-scale clinical audit where the dataset will only include variables that are routinely documented as part of clinical care.

  • 2. All patient data will be anonymized.

  • 3. Critically ill patients often have a decreased level of consciousness, which would make informed consent difficult. This would result in a biased dataset, which data which is not generalizable.

  • 4. We request the use of "broadcasting" signage to inform patients and families at the participating sites about the study.

  • 5. A precedent for a waiver of consent has been set internationally with the EuSOS and ASOS studies. In EuSOS, consent was waived in 27 of the 28 European countries participating, and in the ASOS-1 and ASOS-2 consent was waived in most hospitals.

  • Enrolment/Recruitment Questions

    Should local teams recruit all critically ill patients admitted to hospital?

    Recruitment includes all in-hospital patients, and not only critically ill patients. All in-hospital patients are recruited on Day 1 of recruitment. All patients are recruited at their ward within the hospital on Day 1 of the study. i.e. this is cross-sectional study.

    How do I complete the screening log?

    Every hospital has to submit a screening log for the day of recruitment. This is a separate case record form (CRF) which must be submitted. All good research should include all eligible patients in the study. It is necessary to know how many patients were recruited at your hospital to demonstrate that we have conducted good research. This is what we use to generate the study recruitment flow diagram that you will see in all good research papers. The screening log reports the total number of patients who are inpatients in the hospital on the day of recruitment (i.e., eligible patients for ACIOS), and the number who were recruited and the number who were not recruited. We also need to know the number and reasons for the patients not recruited. Please note that the number of patients recruited and the number of patients not recruited should be equal to the number of admitted patients in the hospital. e.g 1000 patients recruited and 5 patients not recruited = 1005 patients admitted in hospital. If these do not add up, there is an error that needs to be corrected.

    How many hospitals do we expect and what are the steps to getting hospitals recruited for the study?

    Ideally, we would like as many hospitals as possible, so that the data is representative of the true incidence of critical illness. It is also important that we get complete and accurate data. To recruit a hospital, a hospital leader should be identified following which a local hospital investigator team should be created. The recruitment period is between September and November, so timing is important to ensure the hospitals are ready.

    Is there any specific information available to assist with the training of local data collectors?

    We have a manual of ‘Standard Operating Procedures’. It will assist with hospital preparation for the study, and training for the hospital ‘clinical research team’. The manual can be downloaded here: ACIOS-Standard-operating-procedures-handbook-v2.0

    Please provide further information on the sample size.

    From previous continental studies, we expect to recruit about 10 000 patients. We expect an in-hospital mortality of approximately 2%, and a prevalence of critical illness of approximately 20% with a mortality of at least 10%. Based on these estimates, a sample size of 10 000 patients would allow us to:
  • 1. Describe the in-hospital mortality rate with a 95% confidence interval of 0.5%

  • 2. Describe the in-hospital critical illness mortality rate with a 95% confidence interval of 2.6%

  • 3. Allow for the entry of at least 20 risk factors into a model of critical illness mortality, based on an expected mortality event rate of 200 deaths, while abiding by the 10 events per variable rule (Peduzzi P, Concato J, Kemper E, et al. A simulation study of the number of events per variable in logistic regression analysis. J Clin Epidemiol 1996;49(12):1373-9. doi: S0895-4356(96)00236-3).

    The expected sample size is therefore sufficient to adequately address the objectives of this study.

    How long is the patient recruitment period?

    Data is collected for one day in each hospital in the period September to November 2023. On the specified day of data collection, every patient fulfilling the inclusion criteria in every department and ward in the hospital will be included in the study.

    How long is patient follow-up?

    Until hospital discharge or death, censored at 7 days after inclusion.

    Are any new patients included after the initial recruitment day?

    No, no new patients are included in the follow-up period after the first recruitment day.
  • Data Collection

    Which information/data is collected by interviewing the study participants and which data may be collected from medical records?

  • Hospital level data: On page 10 of the protocol, hospital-level data collection may be obtained from the medical officer-in-charge or other relevant hospital clinicians or administrators at the hospital. The required data is in the Hospital CRF.

  • Patient level data: The patient demographics, medical information, and current care provided will be collected from both the patient and the clinical team. Importantly, all vital signs need to be measured by the study team (investigators). This is to ensure the data integrity of the vital signs. Only if the patient refuses to have the vital signs physically measured, or if it is not possible for the investigators to measure the vital signs, will it be acceptable to access the recorded nursing or clinical notes for the vital signs data.

  • Patient CRF Questions

    For an intubated patient, what does one mark down for airway patency from the 3 responses listed on the CRF?

    This question is to understand if the patient currently has a non-clear airway (and therefore is critically ill), so the data collector should listen and if the intubated airway is clear then tick “normal”, if there is are upper-airway sounds then “partial obstruction”, and if the patient cannot get any air into their lungs then “complete obstruction”. If the patient is/is not intubated is captured in the “airway action” question.

    If a patient is referred to another hospital before the end of follow-up, are they recorded as alive or do we follow up their outcome in the other hospital?

    This study is limited to the hospital in which the patient was recruited. So, the patient should be recorded as alive (as he or she was discharged from the hospital in which they were recruited). They should not be followed up in the other hospital.

    How do we use the pain scale?

    We want to know each patient’s worst pain in the last 24 hours. If a patient is struggling to understand the numbers on the scale, show them the vertical scale, ignore the numbers, and instruct them to “indicate on the scale where was your worst pain in the last 24 hours if the top of the scale represents the worst pain you can imagine and the bottom of the scale represents no pain.”

    Hospital Information Sheet

    What do you mean by ‘population served’?

    Population served is the size of the population that is treated by that hospital. It is the population size of the drainage or catchment area of the hospital.

    For consumables, what exactly do we mean by ‘nutrition’?

    Any nutrition that can be provided in an NG tube for a patient who is unable to eat themselves.

    What do we mean with ‘high care’ bed?

    High care unit/HDU: A unit or ward or part of a ward which is dedicated to providing an increased level of care when compared to a general ward. High care units often have increased nurse:patient ratios, more equipment and more advanced care such as oxygen, CPAP, vasopressors etc. This does not include units with mechanical ventilation, as that is an ICU. Includes recovery rooms providing an increased level of care.

    What do we mean with ‘ICU’ bed?

    ICU: A unit or ward which is dedicated to providing an increased level of care when compared to a general ward or high care unit including mechanical ventilation. <\p>

    In a hospital with multiple wards, what are the definitions of availability regarding equipment (For example if a pulse oximeter is always available in one ward and never in another will it be recorded as sometimes for the hospital)?

    The hospital CRF deals with equipment at a hospital-level in general. In this case - if a pulse oximeter is always available somewhere in the hospital then the answer should be always.

    If there is a pulse oximeter in the store but not available for use on patients on the ward at the time is that available or not available?

    If there is only a pulse oximeter in a store and it is not used for patient care then it should be indicated as unavailable.

    Study Operational Questions

    How much time do you think it will take to see a patient for the Day 1 assessment: that is history, vital signs measurement and recording on the case record form (CRF)?

    We estimate that the investigators should expect that about 5 minutes is needed per patient.

    Participating Countries

    Countries confirmed to be participating in ACIOS:

    • Benin

    • National Leader: Eugene Zoumenou

    • Botswana

    • National Leader: Alemayehu Bedada

    • Burkina Faso

    • National Leader: Bertille Ki Kelan

    • Burundi

    • National Leader: Gilles Eloi Rwibuka

    • Cameroon

    • National Leader: Ntogwiachu Daniel Kobuh
      National Leader: Raymond Ndikontar

    • Cape Verde

    • National Leader: Romina Rodrigues
      National Leader: Clara Brito

    • Congo

    • National Leader: Gilles Niengo Outsouta
      National Leader: Marie Elombila

    • Democratic Republic of the Congo

    • National Leader: Dolly Munlemvo
      National Leader: Martin Mukenga

    • Djibouti

    • National Leader: Ahmed Mohamed
      National Leader: Abdo Abdallah Moussa

    • Egypt

    • National Leader: Mahmoud Elfiky

    • Ethiopia

    • National Leader: Fitsum Kefle
      National Leader: Tirunesh Busha Gemechu
      National Leader: Yared Boru Firissa

    • Gabon

    • National Leader: Laurence Essola

    • Gambia

    • National Leader: Mustapha Bittaye
      National Leader: Abubacarr Jagne

    • Ghana

    • National Leader: Christian Owoo
      National Leader: Daniel Sottie

    • Kenya

    • National Leader: Timothy Murithi Mwiti

    • Lesotho

    • National Leader: Mpho Seleke

    • Liberia

    • National Leader: Musavuli Juvenal

    • Libya

    • National Leader: Muhammed Elhadi

    • Malawi

    • National Leader: Wakisa Mulwafu

    • Mali

    • National Leader: Coulibaly Youssouf
      National Leader: Coulibaly Mahamadoun

    • Mauritius

    • National Leader: Veekash Gobin
      National Leader: Kushal Ramkalawan

    • Morocco

    • National Leader: Ahmed Rhassane El Adib
      National Leader: Meryem Essafti

    • Mozambique

    • National Leader: Dino Lopes
      National Leader: Atilio Morais

    • Namibia

    • National Leader: Kaveto Sikuvi

    • Niger

    • National Leader: Maman Sani Chaibo

    • Nigeria

    • National Leader: Adesoji O Ademuyiwa
      National Leader: Babatunde Babasola Osinaike

    • Rwanda

    • National Leader: Paulin Banguti

    • Senegal

    • National Leader: Mamadou Mour Traore

    • Sierra Leone

    • National Leader: Zak Smalle
      National Leader: Eva Hanciles

    • Somalia

    • National Leader: Mohamed Omar

    • Somaliland

    • National Leader: Hassan Daoud
      National Leader: Mohamed Faisal

    • South Africa

    • National Leader: Juan Scribante

    • South Sudan

    • National Leader: Venansio Ajawin
      National Leader: Ajawin Anthony

    • Sudan

    • National Leader: Tarig Fadalla
      National Leader: Alshaima Koko

    • Tanzania

    • National Leader: Tim Baker
      National Leader: Karima Khalid

    • Tunisia

    • National Leader: Nahla Kechiche

    • Uganda

    • National Leader: Adam Hewitt-Smith
      National Leader: Arthur Kwizera

    • Zimbabwe

    • National Leader: Pisirai Ndarukwa
      National Leader: Newten Handireketi

      If you want to participate in the ACIOS Study, feel free to contact us at This email address is being protected from spambots. You need JavaScript enabled to view it.