Project Name
Probiotics for Antibiotic Associated Diarrhoea (including Clostridium difficile) in Care Homes: establishing the platform and a randomised controlled trial (The PAAD Study)


National Institute for Health Research

Principal Investigator
Prof Chris Butler

Stephen Allen, Antony Bayer, Ben Carter, David Cohen, Donna Duncan, Dawn Hill, Kerry Hood, Robin Howe, Antony Johansen, Jacqueline Nuttall, Meirion Evans.

Type of study
Observational and RCT

There is surveillance data from the US and UK, and UK clinical experience to suggest that antibiotic associated diarrhoea (AAD) including C.difficile-associated diarrhoea (CDAD) is an important problem in Care Homes in the UK. There are strong grounds for evaluating probiotics in conjunction with antibiotic treatment to prevent AAD in Care Homes, but this has never been properly evaluated in a clinical trial. However, before a trial is justified, the importance of the problem to the Independent care home sector and NHS, and a firm basis for sample size calculation and trial planning need to be more clearly established.

The introduction of probiotics in conjunction with antibiotic treatment could lead to a significant reduction in AAD as antibiotic treatment is common in this group of people; spread is a particular risk, and patient frailty increases risk of acquisition and of complications. Diarrhoea in this group can lead to serious illness resulting in hospital admissions, cause illness in fellow Care Home residents, increase vulnerability through reduced nutrition and dehydration, result in ongoing incontinence, cause urinary tract infections, and have a profoundly negative impact on dignity. Therefore, we propose a two-phase study. Phase one will establish the descriptive data we need to confirm both the magnitude of the problem and that our sample size calculation assumptions are correct. Knowing the amount and nature of antibiotics prescribe in Care Homes and describing AAD and CDAD will be useful in its own right. If justified, Phase 2 will be a randomised controlled trial to generate robust evidence that fills an important gap in the evidence base about the use of probiotics in conjunction with antibiotic treatment in service users in Care Homes.

PAAD is a two phase study; the first phase is a prospective observational study to indentify the scope of the problem, and incidence of antibiotic associated diarrhoea (AAD) and C.difficile-associated diarrhoea (CDAD) in care homes. This first phase will also inform the trial design and pilot procedures for Phase 2.  Phase 2 is a randomised controlled trial to assess whether AAD is prevented or ameliorated in care home service users receiving antibiotics by the administration of a probiotic alongside the antibiotic.

Start date
July 2010

End date
January 2014

Further Info
The PAAD study on the HTA website