Cystic fibrosis (CF) is a multisystem disease characterized by viscid secretions in multiple organ systems. Lung infection and damage account for most of the disease burden. Acute changes in respiratory signs and symptoms termed Pulmonary Exacerbations require treatment with intravenous antibiotics and hospital admission. These episodes cause substantial disruption to people's lives and impact on lung function, quality of life and lifespan. Current treatment regimes require improvement but further study is needed to identify who might benefit from a different approach.

This observational study aims to assess if multi-dimensional measurements taken during treatment correspond with later treatment response. This may allow us to personalise treatment more effectively in the future and to better understand how individuals respond to treatment.

Pulmonary Exacerbations in CF require treatment with intravenous (IV) antibiotics and hospital admission for between 10-21 days. These episodes cause substantial disruption to people's lives and impact on lung function, quality of life and lifespan.Robust evidence to support current treatment approaches is lacking with awareness that current regimes could be optimised.

As yet there is no model for predicting how patients with CF will respond to IV antibiotic treatment- other than clinical judgement and lung function response.This is due to lack of robust measures to identify clinical response at the time of treatment and safely predict later clinical outcomes. The heterogeneity of the 21st Century CF population means a multi-dimensional composite measure is needed. This study has therefore been designed to provide an overall picture of people's response including clinical, biochemical and patient related outcome measures. Using multi-dimensional assessment we hope the measures assessed in this study will give a better picture of how people feel and how they respond to treatment.

Inclusion Criteria:

1. Patients attending the adult service with a confirmed diagnosis of CF by sweat test or genotype
2. Able to provide written informed consent
3. Able to understand and comply with protocol requirements and instructions
4. Confirmed Pulmonary Exacerbation requiring treatment with intravenous antibiotics using defined criteria (Physician and patient agreed need for admission for intravenous antibiotic treatment)

Exclusion Criteria:

1. Previous recipient of a lung or other solid organ transplant
2. Inability to complete questionnaires
3. Current enrolment in other investigational medicinal product randomised trial
4. Admission for reasons other than pulmonary exacerbation of CF

Adults with a confirmed diagnosis of Cystic Fibrosis being admitted for treatment with intravenous antibiotics for a pulmonary exacerbation using defined criteria (Physician and patient agreed need for admission for intravenous antibiotic treatment)

No individual participant data will be made available to maintain confidentiality