Page 313 - SAHCS HIVMed Journal Vol 20 No 1 2019

Page 2 of 7 Original Research

Previous SA studies of BME utility have confirmed MTB as marrow culture or simultaneous tissue or fluid sampling
the most frequent diagnosis. The last such study analysed elsewhere in the patient provided positive identification of
data from 2004 to 2007. But since 2004, access to antiretroviral the pathogen.
therapy (ART) has increased considerably. The diagnosis of
15
MTB infection has similarly improved following the If relevant clinical information or data were not available on
introduction of routine geneXpert MTB/RIF assessment of the NHLS database, the individual patient’s hospital records
sputum and other body tissues and fluids in the clinics and were obtained and reviewed. Sputum for geneXpert
hospitals of SA. What effect will these changes have on the MTB/RIF was routinely sent on all ID ward patients with a
16
future usefulness of BME in SA patients with suspected and productive cough. Where indicated, the following tests were
difficult to diagnose infections? also performed: lumbar puncture, pleural tap or fine needle
aspirate. A BME was performed if these investigations failed
Methods to provide a diagnosis. The results of all investigations were

Study design and setting obtained from the NHLS database.
This was a retrospective record review of bone marrow For the purposes of this study, the term ‘unique diagnosis’
aspirate and trephine examinations performed on adults refers to any diagnosis made on the BME that was not made
admitted to the infectious disease (ID) ward of the Charlotte with any other diagnostic tests or if the BME provided an
Maxeke Johannesburg Academic Hospital (CMJAH), in answer more timeously than alternative tests. In particular,
Johannesburg, SA, from 01 January 2012 to 31 December 2014. the latter refers to bone marrow cultures that flagged
positive before other specimens. These ‘unique’ results
Study population were important for patient care and may have influenced
subsequent outcomes.
Any patients, irrespective of their suspected diagnosis and
HIV status, who had a BME in the ID ward during the study Statistics
period were included in the study. There were no exclusion
criteria. Patients admitted to the ID ward included any Statistica, version 13, and Stata were used to analyse the data.
patient aged ≥ 16 years with a suspected ID that may or may Descriptive statistics were used for patient demographics.
not have potentially required isolation during their hospital Means and standard deviations were used for haematological
stay, examples of which were patients with suspected parameters. The Student’s t-test was used for comparison
tuberculosis, meningitis and opportunistic infections related between continuous data with a normal distribution. The
to HIV infection. Mann–Whitney-U test was used in comparisons between
data without a normal distribution, specifically in the
Data collection and definitions comparison between possible predictive variables and unique
diagnoses. A statistically significant result was defined as a
The results of the bone marrow aspirate and trephine studies p-value of < 0.05. Odds ratios (OR) were calculated for
were obtained from the National Health Laboratory Services’ predictive determinants of a unique diagnosis on BME.
(NHLS) database. Data were extracted from these reports
and transferred to a standardised data collection sheet. Each Ethical consideration
record was allocated a number and identifying features were
removed. Only laboratory tests performed at the time of or Ethics approval was obtained from the University of the
within a month before or after the BME were used for this Witwatersrand Human Research Ethics Committee (clearance
analysis. number M150847).

The parameters documented were the patients’ age, gender, Results
HIV status, CD4 and viral load (VL) as well as pre-BME Baseline characteristics
blood test results, namely the full blood count, reticulocyte
production index, and vitamin B12, ferritin and folate levels. A total of 327 bone marrow aspirate and trephine examinations
Cytopenias were recorded. The indications for the BME as were carried out in the adult ID ward during the study
well as the final clinical diagnoses were documented. The period. The study population consisted of 162 (49.5%) males
diagnosis of MTB on BME was made through a positive bone and 165 (50.5%) females. The mean age of the study
marrow culture and/or positive MTB polymerase chain population was 36 years with a range of 17–65 years.
reaction (PCR) test. At the time of the study direct PCR testing
of bone marrow for MTB was not routine practice; where Overall, 314 patients (96%) were HIV-seropositive and 12
such data was available it has been included in the study. The HIV-seronegative (3.7%). One patient’s HIV status was
diagnosis of MAC was made on a positive bone marrow unknown. Amongst those with HIV infection, the median
culture. The presence of acid-fast bacilli on Ziehl–Neelsen CD4 cell count was 47 cells/mm (1 cells/mm – 1069 cells/
3
3
3
(ZN) stain and/or that of granuloma on trephine examination mm ) and 271 patients (86.3%) had a CD4 cell count of ≤ 200
3
suggested a likely mycobacterial infection. However, the cells/mm . There were 128 patients on ART (40.8%) at the
microbiological diagnosis remained unconfirmed unless time of the bone marrow investigation.
http://www.sajhivmed.org.za 306 Open Access