Deep Neural Network (DNN) prediction models have emerged as transformative technologies in modern healthcare analytics and clinical diagnosis. These advanced computational systems utilize multiple hidden layers to process vast and complex medical datasets, enabling accurate disease prediction, patient monitoring, medical image analysis, and personalized treatment recommendations. The integration of artificial intelligence with healthcare has significantly improved diagnostic precision, reduced human error, and accelerated clinical decision-making processes. DNN models are capable of learning intricate patterns from electronic health records, genomic data, radiological images, and wearable sensor outputs, thereby supporting early disease detection and preventive healthcare strategies. In recent years, healthcare institutions and researchers have increasingly adopted deep learning frameworks such as Convolutional Neural Networks (CNNs), Recurrent Neural Networks (RNNs), and Long Short-Term Memory (LSTM) networks for medical applications including cancer detection, cardiovascular risk assessment, diabetic retinopathy diagnosis, and neurological disorder prediction. Despite their advantages, challenges such as data privacy concerns, computational complexity, lack of interpretability, and high training costs remain critical issues. This study explores the architecture, applications, methodologies, advantages, and limitations of DNN prediction models in healthcare analytics and diagnosis, highlighting their potential to revolutionize intelligent healthcare systems and improve patient outcomes globally.