Correlation between Pain and Quality of Life in Patients with Venous Ulcers Attended in Primary Health Care: Cross-sectional Study Conducted in Brazil

This study aimed to verify the association and correlation between pain and QoL in people with VU assisted in Brazilian PHC. Descriptive, observational, cross-sectional study with a quantitative approach, carried out from August to October 2019, with patients treated at the PHC in the municipality of Parnamirim, State of Rio Grande do Norte, Brazil. The city has 29 Basic Health Units (UBS) distributed among the 23 neighborhoods of the city, which has a population of 272,490 inhabitants and is located in the Metropolitan Region of Natal, the state capital. Before data collection, each health unit was previously visited to obtain the total number of people with VU treated, which totaled 157 patients. Based on this quantity, the sample calculation was performed using an online formula of quantitative variables for finite populations (https://calculareconverter.com.br/calculo-amostral/). A population size of 157 was considered, with a confidence level of 95% and a margin of error of 5%, resulting in 112 individuals. All units could be consulted and the final sample had representatives from all UBS. A total of 103 individuals who were located and surveyed completed the study. The Short Form Health Survey 36 (SF-36) and the Visual Analog Pain Scale (VAPS) were used. Data collection took place in the form of face-to-face interviews during consultations in the office of the specialized service in VU treatment and were guided by the questions of the selected instruments. For nominal variables, the normality test (Kolmogorov-Smirnov) was applied, identifying a non-normal sample. For sample characterization, absolute (n) and relative (%) frequencies were used. Pearson's non-parametric chi-square test was used to assess the association between sample characteristics and the presence of ulcers, and the percentiles with the SF-36 domains and dimensions. The Kruskal-Walis test was used to assess the association between the domains and dimensions of the SF-36 instrument and the pain scale, and the Spearman Rho test was used to assess the correlation (r) between these scalar variables of pain and QOL . In the correlation analysis, we adopted the following parameters to classify the correlation strength: weak &lt;0.39, moderate between 0.40 and 0.50, and strong correlation &gt;0.50. By Cronbach's α test, the SF-36 was evaluated with good internal consistency, due to α=0.78, in which values greater than 0.70 reveal good consistency. For all tests, we considered a 5% margin of error, a 95% Confidence Interval (CI) and a statistical significance value when p&lt;0.05. 103 patients participated in the study. Higher QoL scores associated with moderate pain were found, especially in the Physical role functioning, Physical functioning and Vitality domains. The correlation analysis pointed out its greater strength (moderate) in the interaction between the highest scores in the Physical role functioning and Emotional role functioning domains and the lowest pain levels.本研究旨在验证巴西初级卫生保健（Primary Health Care, PHC）机构照护的静脉性溃疡（Venous Ulcer, VU）患者的疼痛与生活质量（Quality of Life, QoL）之间的关联与相关性。本研究为描述性、观察性横断面研究，采用定量研究方法，于2019年8月至10月在巴西北里奥格兰德州帕尔纳里宁市的初级卫生保健机构开展，研究对象为该机构收治的静脉性溃疡患者。该市共设有29个基础卫生单元（Unidade Básica de Saúde, UBS），分布于全市23个街区，总人口272490人，地处州府纳塔尔都会区。数据收集前，研究人员预先走访各卫生单元，统计得到收治的静脉性溃疡患者共计157例。基于该样本量，采用针对有限总体的定量变量样本量计算公式（https://calculareconverter.com.br/calculo-amostral/）进行样本量估算，设定置信水平为95%、误差边际为5%，最终计算得到所需样本量为112例。所有卫生单元均纳入调研范围，最终样本覆盖全部基础卫生单元。最终共有103名成功寻访并完成调研的受试者参与本研究。本研究采用简明健康调查问卷36项版（Short Form Health Survey 36, SF-36）与视觉模拟疼痛量表（Visual Analog Pain Scale, VAPS）进行数据收集。数据采集于静脉性溃疡专科诊疗诊室的就诊期间通过面对面访谈完成，由研究人员按照所选量表的问题指引进行询问。针对名义变量，本研究采用Kolmogorov-Smirnov正态性检验，结果显示样本不符合正态分布。样本特征描述采用绝对频数（n）与相对频数（%）。采用Pearson非参数卡方检验评估样本特征与溃疡患病情况、SF-36量表各领域及维度百分位数之间的关联。采用Kruskal-Walis检验分析SF-36量表各领域、维度与疼痛量表得分之间的关联，采用Spearman Rho相关分析评估疼痛与生活质量这两个计量变量间的相关系数（r）。在相关分析中，本研究采用以下标准对相关强度进行分类：弱相关（r<0.39）、中度相关（0.40≤r≤0.50）、强相关（r>0.50）。通过Cronbach's α系数检验评估SF-36量表的内部一致性，结果显示α=0.78，符合内部一致性良好的判定标准（α>0.70提示内部一致性良好）。所有统计检验均设定5%的误差边际、95%置信区间（Confidence Interval, CI），并以p<0.05作为具有统计学显著性的判定标准。本研究共纳入103例患者。结果显示，中度疼痛患者的生活质量得分更高，尤其体现在躯体角色功能、躯体功能与活力领域。相关分析表明，躯体角色功能与情绪角色功能领域得分越高、疼痛程度越低的受试者，其相关强度越强（呈中度相关）。