Table 2. Characteristics of included studies.
| Author and year of publication | Type of study | Country | Period of study | Setting (source population) | Altitude (meters above sea level) | Cut off of Sp02 used | Diagnostic criteria for ALRI | Age group (months) | Other characteristics of the study population | ALRI mortality+ | N° of children evaluated for hypoxemia |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chisti 2011 | CO | BANGLADESH | 2007 | Hospital (Urban) | 4 | 90% | Clinical WHO | 0–59 | All severe ALRI; All ALRI and diarrhoea | 12.1 | 198 |
| Chisti 2013 | CC | BANGLADESH | 2011–2012 | PICU (Urban) | 4 | 90% | Radiological | 0–59 | All severe ALRI; All severe acute malnutrition | ─ | 140 |
| Demers 2000 | CO | CENTRAL AFRICAN REPUBLIC | 1996–1997 | Hospital (Urban) | 386 | Various* | Clinical WHO | 0–59 | - | 12.5 | 392 |
| Djelantik 2003 | CO | INDONESIA | 1999–2001 | Three Hospitals (Rural) | 26 | 85% | Clinical WHO | 0–23 | All severe ALRI | 11.6 | 4306 |
| Duke 2001 | CO | PNG | 1998–1999 | Hospital (Rural) | 1600 | Various* | Clinical WHO combined with PNG guidelines | 1–59 | All severe ALRI; All with Sp02<85% | 6.5 | 703 |
| Graham 2011 | CO | MALAWI | 2005–2006 | Hospital (Urban) | 1039 | 90% | Clinical WHO | 2–156 (12%>60) | All severe ALRI; HIV infected >50% | 10.1 | 327 |
| Junge 2006 | CO | GAMBIA | 1993–1994 | Hospital (Urban) | 29 | Various* | Clinical | 41%<12 | - | 4.6 | 436 |
| Mc Nally 2007 | CO | SOUTH AFRICA | 2001–2002 | Hospital (Urban) | 22 | 92% | Clinical WHO | 1–59 | All severe ALRI; >50% HIV infected | 15.1 | 358 |
| Mwaniki 2009 | CO | KENYA | 2002–2005 | Hospital (Rural) | Sea level | 90% | Clinical WHO | 0–59 | - | 7.8 | 5489 |
| Nantanda 2008 | CO | UGANDA | 2005–2006 | Hospital (Urban) | 1260 | 92% | Clinical WHO | 2–59 | All severe ALRI | 15.3 | 157 |
| Nantanda 2014 | CO | UGANDA | 2011–2012 | Hospital (Urban and Rural) | 1260 | 92% | Clinical WHO ° | 2–59 | Severe ALRI | 3.6 | 614 |
| Onyango 1993 | CO | KENYA | 1989 | Hospital (Urban) | 1670 | 90% | Clinical | 0–36 | - | 10.0 | 209 |
| Reed 2012 | CO | SOUTH AFRICA | 1998–2001 | Hospital (Urban) | 1753 | 90% | Clinical | <24 | - | 7.2% | 4148 |
| Rodríguez 2010 | CC | COLOMBIA | 2007–2008 | Four Hospitals (Ward+PICU) (Urban) | 2640 | 90% | ICD-10 death certificate for ALRI and clinical records | <60 | - | ─ | 226 |
| Sigauque 2009 | CO | MOZAMBIQUE | 2004–2006 | Hospital (Rural) | 50 | 90% | Clinical WHO | 0–23 | All severe ALRI | 6.5 | 584 |
| Smyth 1998 | CO | ZAMBIA | 1994–1995 | Hospital (Rural) | 1150 | 90% | Clinical WHO | 1–59 | All severe ALRI | 14.6 | 158 |
| Usen 1999 | CO | GAMBIA | 1993–1995 | Two Hospitals (Urban) | 2 | 90% | Clinical | 2–33 | - | 3.4 | 1072 |
| Zhang 2013 | CO | CHINA | 2007–2010 | PICU (Urban) | 4 | 92% | Clinical WHO | 0–60 | All severe ALRI | 5.8 | 707 |
* Demers used the following cut-offs: > = 95; 90–94.9; 85–89.9; <85. We grouped results as follows: > = 90; <90.
Duke used the following cut-offs: 70–84; 50–69; <50. We grouped results as follows: 70–84 vs < 70.
Junge used the following cut-offs: >94; 90–94; <90. We grouped results as follows: > = 90 vs <90.
° After admittance, children were further diagnosed using further South African Guideline for bronchiolitis, and GINA guidelines for asthma