Nurses are central members of the healthcare workforce, and the wellbeing of nurses is critical to the safety and efficiency of healthcare delivery (Wakefield, Williams, Le, & Flaubert, 2021). Nurses integrate science, critical thinking, empathy, compassion, and empowerment as they provide care, yet are often left without empathy, acceptance, or support extended to them (Diaw, Sibeoni, Manolios, et al., 2020). This can lead to nurses feeling unseen, isolated, and detached from their work. While nurses are generally regarded as capable, enduring, and content, evidence indicates that nurse wellbeing is at risk. Nurses experience high levels of depression (32 %), anxiety (41 %), addiction (20 %), and suicidality (1.4 % higher risk than the general population) (Davidson, Proudfoot, Lee, Terterian, & Zisook, 2020; Maharaj, Lees, & Lal, 2019; Monroe & Kenaga, 2011). The global pandemic caused by SARs CoV-19 (COVID-19) added to the healthcare workforce's existing burden with evidence of heightened depression, anxiety, and insomnia since the pandemic's start (Lai, Ma, Wang, et al., 2020). When nurses are unwell, patient care suffers (Wakefield et al., 2021).

The Future of Nursing 2020–2030 report highlights the need to promote nurses' physical, mental, moral, and social health (Wakefield et al., 2021). Wellbeing is a state of optimal functioning and quality of life that stems from a complex interplay of physical, emotional, mental, social, and spiritual factors (National Academy of Medicine, 2019). While wellbeing is challenging to measure explicitly, signs of suboptimal wellbeing are found in rates of chronic physical and mental illnesses. Burnout, the most widely studied symptom of suboptimal wellbeing, impacts approximately 40 % of nurses and is a syndrome that involves emotional exhaustion, depersonalization, and a reduced sense of personal accomplishment (Aiken, Sermeus, Van den Heede, et al., 2012; McHugh, Kutney-Lee, Cimiotti, Sloane, & Aiken, 2011; Ruiz-Fernández, Pérez-García, & Ortega-Galán, 2020). Nurses experiencing suboptimal wellbeing are 26–71 % more likely to commit a medical error (Melnyk, Orsolini, Tan, et al., 2018). There is an inverse relationship between patient satisfaction and suboptimal nurse wellbeing, and patient mortality and hospital-acquired infections both increase when nurses experience burnout (Cimiotti, Aiken, Sloane, & Wu, 2012; McHugh et al., 2011; Vahey, Aiken, Sloane, Clarke, & Vargas, 2004; Welp, Meier, & Manser, 2015). Therefore, addressing nurses' wellbeing is vital to ensuring economic, safe, and efficient patient care.

Loneliness is one factor that may detract from wellbeing. It is defined as distress that occurs when the quantity or quality of social connections is insufficient to meet one's emotional needs (Hawkley & Cacioppo, 2010). Prior research among physicians suggest that loneliness may contribute to burnout (Karaoglu et al., 2015; Rogers, Polonijo, & Carpiano, 2016; Shapiro, Zhang, & Warm, 2015) however, literature on nurse loneliness remains limited. Nursing practice has inherent emotional burdens, time pressures, and physical demands that challenge self-care activities (Sabo, 2006; Taylor & Barling, 2004). Nurses provide emotional support to clients that can lead to feelings of emotional isolation, social disconnection, exhaustion, and depressed mood (Pratt & Jachna, 2015; Sabo, 2006; Taylor & Barling, 2004). Although nursing work is highly relational, nurses may not feel their own emotional needs are recognized, which could contribute to feelings of loneliness (Diaw et al., 2020). Therefore, there is evidence that loneliness is a factor in nurse wellbeing. However, a recent integrative review found no studies that explicitly measured loneliness in nurses (Wood, Brown, & Kinser, 2022). This mixed-methods study aimed to investigate the phenomenon of nurse loneliness and the potential contribution of nurse loneliness to burnout, a relationship that remains unclear. While this study did not seek to explicitly explore the impact of the global pandemic on these variables, this study was conducted during the Delta variant wave.

This study is conceptually grounded in the National Academy of Medicine (NAM) Factors Affecting Clinician Well-Being and Resilience Model, which outlines 73 factors affecting clinician wellbeing (National Academy of Medicine, 2018). Using a systems approach, the model has concentric circles that represent the impact of factors on clinician wellbeing, which ultimately impacts patient wellbeing. Although the NAM model does not name loneliness specifically, several named factors may cluster together under the umbrella of loneliness, with evidence supporting their relationship to loneliness (Aiken, Clarke, Sloane, Sochalski, & Silber, 2002; Dyrbye, Shanafelt, Sinsky, et al., 2017; Hawkley & Cacioppo, 2010; McHugh et al., 2011; Rafii, Oskouie, & Nikravesh, 2004; Rogers et al., 2016; Rushton, Batcheller, Schroeder, & Donohue, 2015; Sabo, 2006; Shapiro et al., 2015; Taylor & Barling, 2004). This study focuses on the potential connection between burnout and loneliness by estimating the prevalence of these states, exploring the relationship between these phenomena, and developing a richer understanding of nurse loneliness (Fig. 1).