Impact of the patient-nurse ratio on health outcomes in public hospitals of the Andalusian Health Service. Ecological study.

Objective: To analyse the patient-nurse ratio and its association with health outcomes in public hospitals of the Andalusian Health Service (SAS).

Method: Cross-sectional ecological study carried out in adult units of 26 Andalusian public hospitals. Data on structure (beds, type of unit, nursing control), management (average stay, index of use of stays, complexity index) and nursing staff were collected. They were extracted from official sources: CMBDA, SAS/Health Council (CS) publications and specific respondents to Nursing Directorates. The patient-nurse ratio was calculated and related to 19 indicators of hospital quality, safety, and mortality. Measures of central tendency and Spearman's correlation coefficient were used for statistical analysis.

Results: A response was obtained from 100% of the Andalusian hospitals. The average patient-nurse ratio in the three shifts was lower in hospitals with a broader portfolio of services-regional scope (11.6), followed by those with a medium portfolio-specialties (12.7) and hospitals with a basic portfolio-county (13.5). By type of unit, the medical units were 11.8 (SD = 1.8) lower than the surgical ones 13.5 (SD = 2.7). Significant differences were only found in medical units of regional hospitals 10.5 (SD = 1.4) and district hospitals 13.03 (SD = 1.46) (p = .001). In critical care, the ratio was greater than 2 patients per nurse in the three groups. When relating the ratio to health outcomes, 5 significant associations were found: pressure ulcers (p = .005), prevalence of nosocomial infections (p = .036), postoperative sepsis (p = .022), zero bacteraemia verification (p = .045) and mortality from heart failure (p = .004).

Conclusions: The results indicate a high patient-nurse ratio in adult hospitalization units and that there is a positive association between the patient-nurse ratio and worse results related to nursing care.